Hardenize Report: posteo.de

Web Security Overview

HTTPS

Web sites need to use encryption to help their visitors know they're in the right place, as well as provide confidentiality and content integrity. Sites that don't support HTTPS may expose sensitive data and have their pages modified and subverted.

For all sites VERY IMPORTANT medium EFFORT

HTTPS Redirection

To deploy HTTPS properly, web sites must redirect all unsafe (plaintext) traffic to the encrypted variant. This approach ensures that no sensitive data is exposed and that further security technologies can be activated.

For all sites VERY IMPORTANT low EFFORT

HTTP Strict Transport Security

HTTP Strict Transport Security (HSTS) is an HTTPS extension that instructs browsers to remember sites that use encryption and enforce strict security requirements. Without HSTS, active network attacks are easy to carry out.

For important sites VERY IMPORTANT medium EFFORT

HSTS Preloaded

HSTS Preloading is informing browsers in advance about a site's use of HSTS, which means that strict security can be enforced even on the first visit. This approach provides best HTTPS security available today.

For important sites VERY IMPORTANT medium EFFORT

Content Security Policy

Content Security Policy (CSP) is an additional security layer that enables web sites to control browser behavior, creating a safety net that can counter attacks such as cross-site scripting.

For important sites IMPORTANT high EFFORT

Email Security Overview

STARTTLS

All hosts that receive email need encryption to ensure confidentiality of email messages. Email servers thus need to support STARTTLS, as well as provide decent TLS configuration and correct certificates.

For all sites VERY IMPORTANT low EFFORT

SPF

Sender Policy Framework (SPF) enables organizations to designate servers that are allowed to send email messages on their behalf. With SPF in place, spam is easier to identify.

For important sites IMPORTANT low EFFORT

DMARC

Domain-based Message Authentication, Reporting, and Conformance (DMARC) is a mechanism that allows organizations to specify how unauthenticated email (identified using SPF and DKIM) should be handled.

For important sites IMPORTANT low EFFORT

DNS Zone

The global DNS infrastructure is organized as a series of hierarchical DNS zones. The root zone hosts a number of global and country TLDs, which in turn host further zones that are delegated to their customers. Each organization that controls a zone can delegate parts of its namespace to other zones. In this test we perform detailed inspection of a DNS zone, but only if the host being tested matches the zone.

Test passed

Everything seems to be well configured. Well done.

Nameserver Names

Nameservers can be referred to by name and by address. In this section we show the names, which can appear in the NS records, the referrals from the parent zone, and the SOA record. In some situations, servers from the parent zone respond authoritatively, in which case we will include them in the list as well.

Nameserver	Operational	IPv4	IPv6	Sources
emea.excedodns.eu. 194.58.192.48 2a01:3f1:48::53				NS REFERRAL
global.excedodns.com. 194.58.198.48 2a01:3f1:3048::53				NS REFERRAL
nordic.excedodns.net. 162.219.55.130 2620:10a:80ec::42				NS REFERRAL
ns01.posteo-dns.de. PRIMARY 185.67.36.40 2a05:bc0:1000::40:1				NS REFERRAL SOA
ns02.posteo-dns.de. 185.67.36.42 2a05:bc0:1000::42:1				NS REFERRAL
ns21.posteo-dns.ch. 185.67.36.42 2a05:bc0:1000::42:1				NS REFERRAL
ns31.posteo-dns.eu. 87.225.252.162 2001:bf0:129::162:1				NS REFERRAL
sto.excedodns.se. 185.42.137.101 2a01:3f0:400::48				NS REFERRAL
world.excedodns.org. 162.219.54.130 2620:10a:80eb::42				NS REFERRAL

Nameserver Addresses

This section shows the configuration of all discovered nameservers by their IP address. To find all applicable nameservers, we inspect the parent zone nameservers for names and glue and then the tested zone nameservers for NS records. We then resolve all discovered names to IP addresses. Finally, we test each address individually.

Nameserver	Sources	Payload Size
162.219.54.130 world.excedodns.org. PTR: world.excedodns.org.	NAME	1232
162.219.55.130 nordic.excedodns.net. PTR: nordic.excedodns.net.	NAME	1232
185.42.137.101 sto.excedodns.se. PTR: sto.excedodns.se.	NAME	4096
185.67.36.40 PRIMARY ns01.posteo-dns.de. PTR: ns01.posteo-dns.de.	NAME, GLUE	1232
185.67.36.42 ns21.posteo-dns.ch. ns02.posteo-dns.de.	NAME, GLUE	1232
194.58.192.48 emea.excedodns.eu. PTR: emea.excedodns.eu.	NAME	4096
194.58.198.48 global.excedodns.com. PTR: global.excedodns.com.	NAME	4096
87.225.252.162 ns31.posteo-dns.eu. PTR: ns31.posteo-dns.eu.	NAME	1232
2001:bf0:129::162:1 ns31.posteo-dns.eu. PTR: ns31.posteo-dns.eu.	NAME	1232
2620:10a:80eb::42 world.excedodns.org. PTR: world.excedodns.org.	NAME	1232
2620:10a:80ec::42 nordic.excedodns.net. PTR: nordic.excedodns.net.	NAME	1232
2a01:3f0:400::48 sto.excedodns.se. PTR: sto.excedodns.se.	NAME	4096
2a01:3f1:3048::53 global.excedodns.com. PTR: global.excedodns.com.	NAME	4096
2a01:3f1:48::53 emea.excedodns.eu. PTR: emea.excedodns.eu.	NAME	4096
2a05:bc0:1000::40:1 PRIMARY ns01.posteo-dns.de. PTR: ns01.posteo-dns.de.	NAME, GLUE	1232
2a05:bc0:1000::42:1 ns21.posteo-dns.ch. ns02.posteo-dns.de.	NAME, GLUE	1232

Start of Authority (SOA) Record

Start of Authority (SOA) records contain administrative information pertaining to one DNS zone, especially the configuration that's used for zone transfers between the primary nameserver and the secondaries. Only one SOA record should exist, with all nameservers providing the same information.

The domain name of the primary nameserver for the zone. Also known as MNAME.Primary nameserver	ns01.posteo-dns.de.
Email address of the persons responsible for this zone. Also known as RNAME.Admin email	hostmaster.posteo.de.
Zone serial or version number.Serial number	1730685659
The length of time secondary nameservers should wait before querying the primary for changes.Refresh interval	3,600 seconds (about 1 hour)
The length of time secondary nameservers should wait before querying an unresponsive primary again.Retry interval	900 seconds (about 15 minutes)
The length of time after which secondary nameservers should stop responding to queries for a zone, assuming no updates were obtained from the primary.Expire interval	604,800 seconds (about 7 days)
TTL for purposes of negative response caching. Negative cache TTL	300 seconds (about 5 minutes)
Time To Live (TTL) indicates for how long a record remains valid. SOA record TTL	300 seconds (about 5 minutes)

Analysis

Nameserver addresses should have reverse names

According to RFC 1912, having reverse DNS configuration in place for every nameserver is a best practice that maximizes the chances of correct DNS operation. Further, some anti-spam techniques use reverse name resolution to allow traffic.

Nameserver A and AAAA records should have matching reverse records

According to RFC 1912, nameserver's PTR records must match their A and AAAA records to ensure maximum interoperability.

No problems detected with the zone configuration

Excellent. This DNS zone is in a good working order. No problems detected.

Backing DNS Queries

Below are all DNS queries we submitted during the zone inspection.

	ID	Server	Transport	Question Name	Type	Status

DNS Records

Correctly functioning name servers are necessary to hold and distribute information that's necessary for your domain name to operate correctly. Examples include converting names to IP addresses, determining where email should go, and so on. More recently, the DNS is being used to communicate email and other security policies.

Test passed

Everything seems to be well configured. Well done.

DNS Records

These are the results of individual DNS queries against your nameserver for common resource record types.

Name	TTL	Type	Data
posteo.de.	300	A	185.67.36.168
posteo.de.	300	A	185.67.36.169
www.posteo.de.	300	A	185.67.36.169
www.posteo.de.	300	A	185.67.36.168
posteo.de.	300	AAAA	2a05:bc0:1000:0:0:0:169:1
posteo.de.	300	AAAA	2a05:bc0:1000:0:0:0:168:1
www.posteo.de.	300	AAAA	2a05:bc0:1000:0:0:0:168:1
www.posteo.de.	300	AAAA	2a05:bc0:1000:0:0:0:169:1
posteo.de.	300	CAA	0 iodef "mailto:hostmaster@posteo.de"
posteo.de.	300	CAA	0 issue "certum.pl"
posteo.de.	300	CAA	0 issue "geotrust.com"
posteo.de.	300	CAA	0 issuewild "geotrust.com"
posteo.de.	300	CAA	0 issuewild "d-trust.net"
posteo.de.	300	CAA	0 issue "d-trust.net"
posteo.de.	300	DNSKEY	257 3 8 AwEAAaf1r7SIqmjxs+kjuXGt/hSwa1IZvMb2ed5zuALoSu80+rAB79lZWSiNCS2Y1MYkIu/OicbRtfV15HEooaeLfduZyFgwWVJK7IgHdqRAkU/2pCuX4arQ8h9SPQLNTccFlH0aP+oAuZPfeCVlqFh0fgMtfPdNOKnk49qClPuND+EWoWsowMyZT4yPF20Uv105tm6A5KRMmK7Lv+pbOZbmCpIfLwmAHcezk+yNq8VF+J0kfzq1NgVt4Pds514x3Q2h8ZI4XkyJll36FwlvGOwZXs477fwsDUT8xMknzCbPY1hCxkRYC8+X+hx6vezsLoSgVctllyS8U0q7MHRMrDPbEhNRcFYDqvxXyLN2hHYOU43WlDKmcUsxIpdwGHh+tg4C/YLsNmWbI19Flf9kGbQqmKDnUkBhbdGcR7RKVaFIfvix
posteo.de.	300	DNSKEY	256 3 8 AwEAAfF+q6BPXteBHRzPhEI3JRznhsI76cql2vfObU1e/EdbWQazph6zsIH4KVAuBJVhotgJCphE0GAzESwG1RjaqNn3ioO8ceHw2OIfsn8eOOyku12+NfSNa2SOfM7c8y5rBaUD8eAfaqxgadL4sNDB9oju9ChA10MkBDONnTdvuCgHDuuqGaIOG+FaBxQAx6Y6LTWmmGmtHoZNi30ubEkzd2JpC1rsn486jTkaf9sb5SLCLRw4vYMdUIMBr0Ldliq/pWWHkkV5I7vOoKj31nQm58165YncHeCG/hPAN+b9iYLqYkfNYB7ahCb82WhEKpw71agcStR0yhFA5BLcf3ywOVs=
posteo.de.	900	MX	10 mx03.posteo.de.
posteo.de.	900	MX	10 mx01.posteo.de.
posteo.de.	900	MX	10 mx04.posteo.de.
posteo.de.	272	NS	ns01.posteo-dns.de.
posteo.de.	272	NS	ns02.posteo-dns.de.
posteo.de.	272	NS	ns21.posteo-dns.ch.
posteo.de.	272	NS	ns31.posteo-dns.eu.
posteo.de.	272	NS	world.excedodns.org.
posteo.de.	272	NS	global.excedodns.com.
posteo.de.	272	NS	nordic.excedodns.net.
posteo.de.	272	NS	sto.excedodns.se.
posteo.de.	272	NS	emea.excedodns.eu.
posteo.de.	300	SOA	ns01.posteo-dns.de. hostmaster.posteo.de. 1730685659 3600 900 604800 300
posteo.de.	300	TXT	"v=spf1 ip4:185.67.36.0/23 ip4:89.146.220.128/29 ip4:89.146.194.160/28 ip4:89.146.230.64/26 ip4:185.67.36.111/32 ip6:2a05:bc0:1000::/64 ~all"
posteo.de.	300	TXT	"84944eaf2fa3496cc8b73383c39b0046330432b19e3400ce8c21052b09194db"
_dmarc.posteo.de.	14400	TXT	"v=DMARC1; p=none; adkim=s; aspf=s"
_mta-sts.posteo.de.	300	TXT	"v=STSv1; id=20210422082040Z"
_smtp._tls.posteo.de.	300	TXT	"v=TLSRPTv1; rua=mailto:tlsrpt@posteo.de"

Backing DNS Queries

Below are all DNS queries we submitted while inspecting the resource records.

	ID	Server	Question Name	Type	Status

DNSSEC

DNSSEC is an extension of the DNS protocol that provides cryptographic assurance of the authenticity and integrity of responses; it's intended as a defense against network attackers who are able to manipulate DNS to redirect their victims to servers of their choice. DNSSEC is controversial, with the industry split largely between those who think it's essential and those who believe that it's problematic and unnecessary.

Test passed

Everything seems to be well configured. Well done.

Analysis

DNSSEC is well configured

Good. This domain name has well-configured DNSSEC.

Useful DNSSEC Tools

Certification Authority Authorization

CAA (RFC 8659) is a new standard that allows domain name owners to restrict which CAs are allowed to issue certificates for their domains. This can help to reduce the chance of misissuance, either accidentally or maliciously. In September 2017, CAA became mandatory for CAs to implement.

Test passed

Everything seems to be well configured. Well done.

CAA Policy Information

The DNS hostname where this policy is located.Policy host	posteo.de
The issue property tag is used to request that certificate issuers perform CAA issue restriction processing for the domain and to grant authorization to specific certificate issuers.issue	certum.pl flags: 0
The issuewild property has the same syntax and semantics as the issue property except that issuewild properties only grant authorization to issue certificates that specify a wildcard domain and issuewild properties take precedence over issue properties when specified.issuewild	geotrust.com flags: 0
The issue property tag is used to request that certificate issuers perform CAA issue restriction processing for the domain and to grant authorization to specific certificate issuers.issue	d-trust.net flags: 0
The issuewild property has the same syntax and semantics as the issue property except that issuewild properties only grant authorization to issue certificates that specify a wildcard domain and issuewild properties take precedence over issue properties when specified.issuewild	d-trust.net flags: 0
The issue property tag is used to request that certificate issuers perform CAA issue restriction processing for the domain and to grant authorization to specific certificate issuers.issue	geotrust.com flags: 0
The iodef property specifies a means of reporting certificate issue requests or cases of certificate issue for the corresponding domain that violate the security policy of the issuer or the domain name holder.iodef	mailto:hostmaster@posteo.de flags: 0

Analysis

Issuance of S/MIME certificates not restricted

This policy doesn't restrict the issuance of S/MIME certificates. Consider using the `issuemail` directive to restrict which CAs, if any, can issue.

Issuance of BIMI not restricted

This policy doesn't restrict issuance of BIMI certificates. Consider using the `issuevmc` directive to restrict which CAs, if any, can issue.

CAA policy restricts issuance

Great. This domain name uses CAA to restrict which CAs are allowed to issue certificates for it.

Policy uses reporting

Good. This policy uses reporting, which means that your contact information is available should someone need to contact you about a CAA violation. Do note that you're not guaranteed to be notified, given that CAs generally don't support notifications yet.

Email (SMTP)

An internet hostname can be served by zero or more mail servers, as specified by MX (mail exchange) DNS resource records. Each server can further resolve to multiple IP addresses, for example to handle IPv4 and IPv6 clients. Thus, in practice, hosts that wish to receive email reliably are supported by many endpoint.

Test passed

Everything seems to be well configured. Well done.

Some TLS and PKI information shown may have been retrieved from cache. The notes provide more information.

Server	Preference	Operational	STARTTLS	TLS	PKI	DNSSEC	DANE
mx04.posteo.de 185.67.36.64 PTR: mx04.posteo.de	10
mx04.posteo.de 185.67.36.71 PTR: mx04.posteo.de	10
mx01.posteo.de 185.67.36.61 PTR: mx01.posteo.de	10
mx01.posteo.de 185.67.36.62 PTR: mx01.posteo.de	10
mx03.posteo.de 185.67.36.70 PTR: mx03.posteo.de	10
mx03.posteo.de 185.67.36.63 PTR: mx03.posteo.de	10

Analysis

Email servers match MTA-STS policy

Good. This host supports MTA-STS, which means that it restricts which MX servers can be used and how they are configured. We've verified that all MX servers listed here match the policy.

Some SMTP server assessments have been retrieved from cache

Some SMTP server assessment results have been retrieved from our cache. Because many hosts point to the same SMTP servers, we use a short-term cache to avoid testing the same SMTP servers over and over again.

Latest cache timestamp: 29 Oct 2024 08:31 UTC

Earliest cache timestamp: 29 Oct 2024 08:30 UTC

Some SMTP server assessments contain partial information

Comprehensive TLS assessments require many connections, which is exactly what many SMTP servers don't like. We implement a two-tier assessment approach. To give you some results as fast as possible, we perform shallow assessments that use only one connection per SMTP server. We then have a background process that performs complete assessments slowly, trying to accommodate each server individually. The results presented here contain partial information. If you come back later we may be able to provide complete assessment resuls.

Email TLS (SMTP)

Transport Layer Security (TLS) is the most widely used encryption protocol on the Internet. In combination with valid certificates, servers can establish trusted communication channels even with users who have never visited them before. Network attackers can't uncover what is being communicated, even when they can see all the traffic.

Test passed

Everything seems to be well configured. Well done.

Some TLS and PKI information shown may have been retrieved from cache. The notes provide more information.

TLS Configuration: mx04.posteo.de (185.67.36.64) Cached

Encryption protocol version determines what features are available for negotiation between client and server.Supported protocols	TLS v1.2
Shows cipher suite configuration for this protocol version.TLS v1.2	Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 Suite ID: 0xc030 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits)
These results have been retrieved from our cache. This row indicates when was that the original test ran.Retrieved from cache	29 Oct 2024 08:31 UTC

Analysis

TLS 1.2 supported

Good. This server supports TLS 1.2, which can provide strong security when configured correctly. This version of the TLS protocol is necessary to provide good security with a wide range of clients that don't yet support TLS 1.3.

Strong key exchange detected

Excellent. All cipher suites on this server rely on strong key exchange. The sweet spot is 2048 bits for DHE and 256 bits for ECDHE. Putting ECDHE suites first guarantees best security and best performance.

Partial results shown

SMTP assessments usually take a long time. To get you some results faster, we initially perform shallow checks. If you come back later we may be able to show you complete results.

Relaxed TLS assessment criteria applied to SMTP on port 25

We apply relaxed assessment criteria when evaluating TLS configuration of SMTP servers on port 25. This is because most delivery agents fall back to delivering via plaintext on failure to negotiate encryption. Some configuration elements that can be abused to attack other ports and protocols (e.g., SSLv2 and export cipher suites) are penalized in the same way as for other protocols. We will review this policy in the future.

TLS Configuration: mx04.posteo.de (185.67.36.71) Cached

Encryption protocol version determines what features are available for negotiation between client and server.Supported protocols	TLS v1.2
Shows cipher suite configuration for this protocol version.TLS v1.2	Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 Suite ID: 0xc030 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits)
These results have been retrieved from our cache. This row indicates when was that the original test ran.Retrieved from cache	29 Oct 2024 08:31 UTC

Analysis

TLS 1.2 supported

Good. This server supports TLS 1.2, which can provide strong security when configured correctly. This version of the TLS protocol is necessary to provide good security with a wide range of clients that don't yet support TLS 1.3.

Strong key exchange detected

Excellent. All cipher suites on this server rely on strong key exchange. The sweet spot is 2048 bits for DHE and 256 bits for ECDHE. Putting ECDHE suites first guarantees best security and best performance.

Partial results shown

SMTP assessments usually take a long time. To get you some results faster, we initially perform shallow checks. If you come back later we may be able to show you complete results.

Relaxed TLS assessment criteria applied to SMTP on port 25

We apply relaxed assessment criteria when evaluating TLS configuration of SMTP servers on port 25. This is because most delivery agents fall back to delivering via plaintext on failure to negotiate encryption. Some configuration elements that can be abused to attack other ports and protocols (e.g., SSLv2 and export cipher suites) are penalized in the same way as for other protocols. We will review this policy in the future.

TLS Configuration: mx01.posteo.de (185.67.36.61) Cached

Encryption protocol version determines what features are available for negotiation between client and server.Supported protocols	TLS v1.2
Shows cipher suite configuration for this protocol version.TLS v1.2	Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 Suite ID: 0xc030 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits)
These results have been retrieved from our cache. This row indicates when was that the original test ran.Retrieved from cache	29 Oct 2024 08:31 UTC

Analysis

TLS 1.2 supported

Good. This server supports TLS 1.2, which can provide strong security when configured correctly. This version of the TLS protocol is necessary to provide good security with a wide range of clients that don't yet support TLS 1.3.

Strong key exchange detected

Excellent. All cipher suites on this server rely on strong key exchange. The sweet spot is 2048 bits for DHE and 256 bits for ECDHE. Putting ECDHE suites first guarantees best security and best performance.

Partial results shown

SMTP assessments usually take a long time. To get you some results faster, we initially perform shallow checks. If you come back later we may be able to show you complete results.

Relaxed TLS assessment criteria applied to SMTP on port 25

We apply relaxed assessment criteria when evaluating TLS configuration of SMTP servers on port 25. This is because most delivery agents fall back to delivering via plaintext on failure to negotiate encryption. Some configuration elements that can be abused to attack other ports and protocols (e.g., SSLv2 and export cipher suites) are penalized in the same way as for other protocols. We will review this policy in the future.

TLS Configuration: mx01.posteo.de (185.67.36.62) Cached

Encryption protocol version determines what features are available for negotiation between client and server.Supported protocols	TLS v1.2
Shows cipher suite configuration for this protocol version.TLS v1.2	Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 Suite ID: 0xc030 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits)
These results have been retrieved from our cache. This row indicates when was that the original test ran.Retrieved from cache	29 Oct 2024 08:31 UTC

Analysis

TLS 1.2 supported

Good. This server supports TLS 1.2, which can provide strong security when configured correctly. This version of the TLS protocol is necessary to provide good security with a wide range of clients that don't yet support TLS 1.3.

Strong key exchange detected

Excellent. All cipher suites on this server rely on strong key exchange. The sweet spot is 2048 bits for DHE and 256 bits for ECDHE. Putting ECDHE suites first guarantees best security and best performance.

Partial results shown

SMTP assessments usually take a long time. To get you some results faster, we initially perform shallow checks. If you come back later we may be able to show you complete results.

Relaxed TLS assessment criteria applied to SMTP on port 25

We apply relaxed assessment criteria when evaluating TLS configuration of SMTP servers on port 25. This is because most delivery agents fall back to delivering via plaintext on failure to negotiate encryption. Some configuration elements that can be abused to attack other ports and protocols (e.g., SSLv2 and export cipher suites) are penalized in the same way as for other protocols. We will review this policy in the future.

TLS Configuration: mx03.posteo.de (185.67.36.70) Cached

Encryption protocol version determines what features are available for negotiation between client and server.Supported protocols	TLS v1.2
Shows cipher suite configuration for this protocol version.TLS v1.2	Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 Suite ID: 0xc030 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits)
These results have been retrieved from our cache. This row indicates when was that the original test ran.Retrieved from cache	29 Oct 2024 08:30 UTC

Analysis

TLS 1.2 supported

Good. This server supports TLS 1.2, which can provide strong security when configured correctly. This version of the TLS protocol is necessary to provide good security with a wide range of clients that don't yet support TLS 1.3.

Strong key exchange detected

Excellent. All cipher suites on this server rely on strong key exchange. The sweet spot is 2048 bits for DHE and 256 bits for ECDHE. Putting ECDHE suites first guarantees best security and best performance.

Partial results shown

SMTP assessments usually take a long time. To get you some results faster, we initially perform shallow checks. If you come back later we may be able to show you complete results.

Relaxed TLS assessment criteria applied to SMTP on port 25

We apply relaxed assessment criteria when evaluating TLS configuration of SMTP servers on port 25. This is because most delivery agents fall back to delivering via plaintext on failure to negotiate encryption. Some configuration elements that can be abused to attack other ports and protocols (e.g., SSLv2 and export cipher suites) are penalized in the same way as for other protocols. We will review this policy in the future.

TLS Configuration: mx03.posteo.de (185.67.36.63) Cached

Encryption protocol version determines what features are available for negotiation between client and server.Supported protocols	TLS v1.2
Shows cipher suite configuration for this protocol version.TLS v1.2	Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 Suite ID: 0xc030 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits)
These results have been retrieved from our cache. This row indicates when was that the original test ran.Retrieved from cache	29 Oct 2024 08:30 UTC

Analysis

TLS 1.2 supported

Good. This server supports TLS 1.2, which can provide strong security when configured correctly. This version of the TLS protocol is necessary to provide good security with a wide range of clients that don't yet support TLS 1.3.

Strong key exchange detected

Excellent. All cipher suites on this server rely on strong key exchange. The sweet spot is 2048 bits for DHE and 256 bits for ECDHE. Putting ECDHE suites first guarantees best security and best performance.

Partial results shown

SMTP assessments usually take a long time. To get you some results faster, we initially perform shallow checks. If you come back later we may be able to show you complete results.

Relaxed TLS assessment criteria applied to SMTP on port 25

We apply relaxed assessment criteria when evaluating TLS configuration of SMTP servers on port 25. This is because most delivery agents fall back to delivering via plaintext on failure to negotiate encryption. Some configuration elements that can be abused to attack other ports and protocols (e.g., SSLv2 and export cipher suites) are penalized in the same way as for other protocols. We will review this policy in the future.

Email Certificates (SMTP)

A certificate is a digital document that contains a public key, some information about the entity associated with it, and a digital signature from the certificate issuer. It’s a mechanism that enables us to exchange, store, and use public keys. Being able to reliably verify the identity of a remote server is crucial in order to achieve secure encrypted communication.

Test passed

Everything seems to be well configured. Well done.

Some TLS and PKI information shown may have been retrieved from cache. The notes provide more information.

Certificate #1 Cached

Leaf certificate

mx01.posteo.de
Issuer: DigiCert
Not Before: 20 Sep 2024 00:00:00 UTC
Not After: 03 Oct 2025 23:59:59 UTC (expires in 10 months 29 days)
Key: RSA 3072 bits
Signature: SHA256withRSA
View details

Names	mx01.posteo.de mx02.posteo.de mx03.posteo.de mx04.posteo.de mxv6.posteo.de
Subject DN	CN=mx01.posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE
Subject Key Identifier	76c49143843989eab460ed21940cf826112f6eaf
Serial	99015c764288473225a1061900dbf5a
Not Before	20 Sep 2024 00:00:00 UTC
Not After	03 Oct 2025 23:59:59 UTC
Validity period	379 days
Key Usage	digitalSignature, keyEncipherment
Extended Key Usage	serverAuth, clientAuth
Must Staple	No
Issuer
Issuer DN	CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Extended Validation (EV)
Authority Key Identifier	keyid:28d2cfee098475ddb5b2b5bf3cd5a0c673885d1f
Parent Certificate	http://cacerts.digicert.com/GeoTrustEVRSACAG2.crt
CRL	http://crl3.digicert.com/GeoTrustEVRSACAG2.crl http://crl4.digicert.com/GeoTrustEVRSACAG2.crl
OCSP	http://ocsp.digicert.com
Certificate Transparency
Signed Certificate Timestamps	20 Sep 2024 19:29:30 UTC \| Google 'Xenon2025h2' log \| Qualified 20 Sep 2024 19:29:30 UTC \| DigiCert Yeti2025 Log \| Qualified 20 Sep 2024 19:29:30 UTC \| DigiCert Nessie2025 Log \| Qualified
Fingerprints
SHA1	d8aa38845f94423a78a1fb9929f70dfc691a393a
SHA256	be243b4a7d29fa1e96cf7207cbe067a6efae1b5043eaa411b331b3d5ba1f4b91
SPKI SHA256	a73a9adb16bd5a4131df79c446438e138da78fbb64d4ebad97017a4fad4ec92e

Analysis

Strong private key

Good. The private key associated with this certificate is secure.

Strong signature algorithm

Good. This certificate uses a strong signature algorithm.

Certificate matches hostname

Good. The provided certificate matches the expected hostnames.

Certificate dates match

Good. The certificate is valid for use at this point of time.

Certificate has not been revoked

Good. This certificate has not been revoked.

Certificate satisfies Apple's CT compliance requirements

Good. This certificate satisfies Apple's CT requirements at present.

Symantec subordinate CA excluded from early expiration

Although the leaf certificate ultimately chains to a Symantec root, it has been issued from an independently-operated subordinate CA that has been excluded from early expiration.

Certificate Chain

Leaf certificate

mx01.posteo.de | be243b4
Not After: 03 Oct 2025 23:59:59 UTC (expires in 10 months 29 days)
Authentication: RSA 3072 bits (SHA256withRSA)
View details

Names	mx01.posteo.de mx02.posteo.de mx03.posteo.de mx04.posteo.de mxv6.posteo.de
Subject DN	CN=mx01.posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE
Subject Key Identifier	76c49143843989eab460ed21940cf826112f6eaf
Serial	99015c764288473225a1061900dbf5a
Not Before	20 Sep 2024 00:00:00 UTC
Not After	03 Oct 2025 23:59:59 UTC
Validity period	379 days
Key Usage	digitalSignature, keyEncipherment
Extended Key Usage	serverAuth, clientAuth
Must Staple	No
Issuer
Issuer DN	CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Extended Validation (EV)
Authority Key Identifier	keyid:28d2cfee098475ddb5b2b5bf3cd5a0c673885d1f
Parent Certificate	http://cacerts.digicert.com/GeoTrustEVRSACAG2.crt
CRL	http://crl3.digicert.com/GeoTrustEVRSACAG2.crl http://crl4.digicert.com/GeoTrustEVRSACAG2.crl
OCSP	http://ocsp.digicert.com
Certificate Transparency
Signed Certificate Timestamps	20 Sep 2024 19:29:30 UTC \| Google 'Xenon2025h2' log \| Qualified 20 Sep 2024 19:29:30 UTC \| DigiCert Yeti2025 Log \| Qualified 20 Sep 2024 19:29:30 UTC \| DigiCert Nessie2025 Log \| Qualified
Fingerprints
SHA1	d8aa38845f94423a78a1fb9929f70dfc691a393a
SHA256	be243b4a7d29fa1e96cf7207cbe067a6efae1b5043eaa411b331b3d5ba1f4b91
SPKI SHA256	a73a9adb16bd5a4131df79c446438e138da78fbb64d4ebad97017a4fad4ec92e

Intermediate certificate

GeoTrust EV RSA CA G2 | 2d140f2
Not After: 02 Jul 2030 12:42:57 UTC (expires in 5 years 7 months)
Authentication: RSA 2048 bits (SHA256withRSA)
View details

Subject DN	CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US
Subject Key Identifier	28d2cfee098475ddb5b2b5bf3cd5a0c673885d1f
Serial	d601262c8a7721a6eab0361e5619580
Not Before	02 Jul 2020 12:42:57 UTC
Not After	02 Jul 2030 12:42:57 UTC
Key Usage	digitalSignature, keyCertSign, cRLSign
Extended Key Usage	serverAuth, clientAuth
Issuer
Issuer DN	CN=DigiCert Global Root G2, OU=www.digicert.com, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Not Applicable
Authority Key Identifier	keyid:4e2254201895e6e36ee60ffafab912ed06178f39
CRL	http://crl3.digicert.com/DigiCertGlobalRootG2.crl http://crl4.digicert.com/DigiCertGlobalRootG2.crl
OCSP	http://ocsp.digicert.com
CA certificate	Yes (pathlen 0)
Fingerprints
SHA1	687d4a4d47014f91217e4a062bbf9d238358943e
SHA256	2d140f20b8a96e2b4d2f1cc5aca5e5a1e7dc56a7491e510906960f38d2d21aef
SPKI SHA256	54751a82af3482c59dbe77c72fffb65d22d9ac0264e08f5df1fc7a37c52f5863

Root certificate

DigiCert Global Root G2 | cb3ccbb
Not After: 15 Jan 2038 12:00:00 UTC (expires in 13 years 2 months)
Authentication: RSA 2048 bits (SHA256withRSA)
View details

Subject DN	CN=DigiCert Global Root G2, OU=www.digicert.com, O=DigiCert Inc, C=US
Subject Key Identifier	4e2254201895e6e36ee60ffafab912ed06178f39
Serial	33af1e6a711a9a0bb2864b11d09fae5
Not Before	01 Aug 2013 12:00:00 UTC
Not After	15 Jan 2038 12:00:00 UTC
Key Usage	digitalSignature, keyCertSign, cRLSign
Issuer
Issuer DN	CN=DigiCert Global Root G2, OU=www.digicert.com, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Self-signed
CA certificate	Yes (pathlen unlimited)
Fingerprints
SHA1	df3c24f9bfd666761b268073fe06d1cc8d4f82a4
SHA256	cb3ccbb76031e5e0138f8dd39a23f9de47ffc35e43c1144cea27d46a5ab1cb5f
SPKI SHA256	8bb593a93be1d0e8a822bb887c547890c3e706aad2dab76254f97fb36b82fc26

Analysis

Certificate chain is correct

Good. This chain contains all the right certificates and in the right order.

Email DANE (SMTP)

DNS-based Authentication of Named Entities (DANE) is a bridge between DNSSEC and TLS. In one possible scenario, DANE can be used for public key pinning, building on an existing publicly-trusted certificate. In another approach, it can be used to completely bypass the CA ecosystem and establish trust using DNSSEC alone.

Test passed

Everything seems to be well configured. Well done.

Some TLS and PKI information shown may have been retrieved from cache. The notes provide more information.

DANE: mx04.posteo.de (185.67.36.64)

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	a73a9adb16bd5a4131df79c446438e138da78fbb64d4ebad97017a4fad4ec92e Leaf certificate: RSA 3072 bits Subject: CN=mx01.posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE Issuer: CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US mx01.posteo.de (RSA 3072 bits)

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	2a2413f46c23290866a3fb9c1658a404bcf6a71373d002a29d67c23ed8df298d

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	2ad38769dc6a92ed98fb7a45514c0a74919ebc9fa13514c5c742c92080a66874

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	13815b2c03f7bd63c54869706428442edab706d5b018a27575ca989129a196d5

Analysis

Valid DANE configuration

Excellent. Your DANE configuration matches the certificate chain(s) provided by the service. Your TLS configuration enjoys the additional benefit of DANE validation.

DANE: mx04.posteo.de (185.67.36.71)

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	a73a9adb16bd5a4131df79c446438e138da78fbb64d4ebad97017a4fad4ec92e Leaf certificate: RSA 3072 bits Subject: CN=mx01.posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE Issuer: CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US mx01.posteo.de (RSA 3072 bits)

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	2a2413f46c23290866a3fb9c1658a404bcf6a71373d002a29d67c23ed8df298d

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	2ad38769dc6a92ed98fb7a45514c0a74919ebc9fa13514c5c742c92080a66874

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	13815b2c03f7bd63c54869706428442edab706d5b018a27575ca989129a196d5

Analysis

Valid DANE configuration

Excellent. Your DANE configuration matches the certificate chain(s) provided by the service. Your TLS configuration enjoys the additional benefit of DANE validation.

DANE: mx01.posteo.de (185.67.36.61)

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	a73a9adb16bd5a4131df79c446438e138da78fbb64d4ebad97017a4fad4ec92e Leaf certificate: RSA 3072 bits Subject: CN=mx01.posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE Issuer: CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US mx01.posteo.de (RSA 3072 bits)

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	2ad38769dc6a92ed98fb7a45514c0a74919ebc9fa13514c5c742c92080a66874

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	2a2413f46c23290866a3fb9c1658a404bcf6a71373d002a29d67c23ed8df298d

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	13815b2c03f7bd63c54869706428442edab706d5b018a27575ca989129a196d5

Analysis

Valid DANE configuration

Excellent. Your DANE configuration matches the certificate chain(s) provided by the service. Your TLS configuration enjoys the additional benefit of DANE validation.

DANE: mx01.posteo.de (185.67.36.62)

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	a73a9adb16bd5a4131df79c446438e138da78fbb64d4ebad97017a4fad4ec92e Leaf certificate: RSA 3072 bits Subject: CN=mx01.posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE Issuer: CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US mx01.posteo.de (RSA 3072 bits)

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	2ad38769dc6a92ed98fb7a45514c0a74919ebc9fa13514c5c742c92080a66874

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	2a2413f46c23290866a3fb9c1658a404bcf6a71373d002a29d67c23ed8df298d

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	13815b2c03f7bd63c54869706428442edab706d5b018a27575ca989129a196d5

Analysis

Valid DANE configuration

Excellent. Your DANE configuration matches the certificate chain(s) provided by the service. Your TLS configuration enjoys the additional benefit of DANE validation.

DANE: mx03.posteo.de (185.67.36.70)

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	2a2413f46c23290866a3fb9c1658a404bcf6a71373d002a29d67c23ed8df298d

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	13815b2c03f7bd63c54869706428442edab706d5b018a27575ca989129a196d5

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	a73a9adb16bd5a4131df79c446438e138da78fbb64d4ebad97017a4fad4ec92e Leaf certificate: RSA 3072 bits Subject: CN=mx01.posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE Issuer: CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US mx01.posteo.de (RSA 3072 bits)

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	2ad38769dc6a92ed98fb7a45514c0a74919ebc9fa13514c5c742c92080a66874

Analysis

Valid DANE configuration

Excellent. Your DANE configuration matches the certificate chain(s) provided by the service. Your TLS configuration enjoys the additional benefit of DANE validation.

DANE: mx03.posteo.de (185.67.36.63)

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	2a2413f46c23290866a3fb9c1658a404bcf6a71373d002a29d67c23ed8df298d

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	13815b2c03f7bd63c54869706428442edab706d5b018a27575ca989129a196d5

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	a73a9adb16bd5a4131df79c446438e138da78fbb64d4ebad97017a4fad4ec92e Leaf certificate: RSA 3072 bits Subject: CN=mx01.posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE Issuer: CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US mx01.posteo.de (RSA 3072 bits)

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	2ad38769dc6a92ed98fb7a45514c0a74919ebc9fa13514c5c742c92080a66874

Analysis

Valid DANE configuration

Excellent. Your DANE configuration matches the certificate chain(s) provided by the service. Your TLS configuration enjoys the additional benefit of DANE validation.

SPF

Sender Policy Framework (SPF) is a protocol that allows domain name owners to control which internet hosts are allowed to send email on their behalf. This simple mechanism can be used to reduce the effect of email spoofing and cut down on spam.

Test passed

Everything seems to be well configured. Well done.

SPF Policy Information Main policy

Host where this policy is located.Location	posteo.de
SPF version used by this policy.v	spf1
This mechanism tests whether the IP address being tested is contained within a given IPv4 network. ip4	185.67.36.0/23
This mechanism tests whether the IP address being tested is contained within a given IPv4 network. ip4	89.146.220.128/29
This mechanism tests whether the IP address being tested is contained within a given IPv4 network. ip4	89.146.194.160/28
This mechanism tests whether the IP address being tested is contained within a given IPv4 network. ip4	89.146.230.64/26
This mechanism tests whether the IP address being tested is contained within a given IPv4 network. ip4	185.67.36.111/32
This mechanism tests whether the IP address being tested is contained within a given IPv6 network. ip6	2a05:bc0:1000::/64
This policy element always matches. It's normally used at the end of a policy to specify the handling of hosts that don't match earlier mechanisms. ~all

Analysis

SPF policy found

Policy text: v=spf1 ip4:185.67.36.0/23 ip4:89.146.220.128/29 ip4:89.146.194.160/28 ip4:89.146.230.64/26 ip4:185.67.36.111/32 ip6:2a05:bc0:1000::/64 ~all

Location: posteo.de

SPF policy is valid

Good. Your SPF policy is syntactically valid.

Policy DNS lookups under limit

Good. Your policy stays under the limit of up to 10 DNS queries. The SPF specification Section 4.6.4. requires implementations to limit the total number of DNS queries. Policies that exceed the limit should not be used and may not work in practice.

Lookups: 0

DMARC

Domain-based Message Authentication, Reporting, and Conformance (DMARC) is a scalable mechanism by which a mail-originating organization can express domain-level policies and preferences for message validation, disposition, and reporting, that a mail-receiving organization can use to improve mail handling.

Feature not applicable, not implemented, or disabled

Your server doesn't support this feature.

DMARC Policy Information

The location from which we obtained this policy.Policy location	_dmarc.posteo.de
DMARC version used by this policy.v	DMARC1
Indicates the policy to be enacted by the receiver at the request of the domain owner. Possible values are: none, quarantine, and reject.p	none
Indicates whether strict or relaxed DKIM alignment mode is required.adkim	s
Indicates whether strict or relaxed SPF alignment mode is required.aspf	s

Analysis

DMARC policy found

Policy: v=DMARC1; p=none; adkim=s; aspf=s

Host: _dmarc.posteo.de

Policy is valid

Good. You have a valid DMARC policy.

Activate DMARC policy

Although syntactically valid, your DMARC policy is effectively disabled. An effective policy must set the value of the 'p' directive to either 'quarantine' or 'reject'. In addition, if the 'pct' directive is present, it must be set to a value other than zero. (The default is 100, which means to apply policy to all emails.)

MTA Strict Transport Security

SMTP Mail Transfer Agent Strict Transport Security (MTA-STS) is a mechanism enabling mail service providers to declare their ability to receive Transport Layer Security (TLS) secure SMTP connections, and to specify whether sending SMTP servers should refuse to deliver to MX hosts that do not offer TLS with a trusted server certificate.

Test passed

Everything seems to be well configured. Well done.

MTA-STS Policy Indicator

Location from which we retrieved the policy indicator.Location	_mta-sts.posteo.de
MTA-STS standard version used by this policy indicator.Version	STSv1
Unique policy identifier, whose value must change every time the underlying policy changes.ID	20210422082040Z

Analysis

MTA-STS policy indicator valid

Good. Your MTA-STS policy indicator is valid.

MTA-STS Policy

The URL from which the policy was obtained.Location	https://mta-sts.posteo.de/.well-known/mta-sts.txt
Policy standard version.version	STSv1
Policy duration, which specifies how long the sending MTAs should remember and enforce the server policy for.max‑age	1,209,600 seconds (about 14 days)
Policy mode, which can be one of 'none', 'testing' and 'enforcing'. Guess which is best! :)mode	enforce
One 'mx' directive specifies one email server pattern that's allowed for this host.mx	mx01.posteo.de
One 'mx' directive specifies one email server pattern that's allowed for this host.mx	mx03.posteo.de
One 'mx' directive specifies one email server pattern that's allowed for this host.mx	mx04.posteo.de
One 'mx' directive specifies one email server pattern that's allowed for this host.mx	posteo.de

Analysis

MTA-STS policy is valid

Good. Your MTA-STS policy is valid.

Policy host certificate is valid

Good. Your MTA-STS policy is delivered via a web server that has a valid publicly trusted certificate. This is a necessary condition for the policy to be recognized.

Policy HTTPS response information

Status code: 200

Length: 117 bytes

Content-Type: text/plain

Certificate: mta-sts.posteo.de

Leaf certificate

posteo.de
Issuer: DigiCert
Not Before: 19 Feb 2024 00:00:00 UTC
Not After: 21 Feb 2025 23:59:59 UTC (expires in 3 months 17 days)
Key: RSA 3072 bits
Signature: SHA256withRSA
View details

Names	posteo.de www.posteo.de lists.posteo.de autoconfig.posteo.de mta-sts.posteo.de api.posteo.de cdn.posteo.de autodiscover.posteo.de
Subject DN	CN=posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE
Subject Key Identifier	69b316ba06f9ffa99789de7dfbeb90808f3ffe61
Serial	ce9a457c6a050a2a55c6ebfeae53d18
Not Before	19 Feb 2024 00:00:00 UTC
Not After	21 Feb 2025 23:59:59 UTC
Validity period	369 days
Key Usage	digitalSignature, keyEncipherment
Extended Key Usage	serverAuth, clientAuth
Must Staple	No
Issuer
Issuer DN	CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Extended Validation (EV)
Authority Key Identifier	keyid:28d2cfee098475ddb5b2b5bf3cd5a0c673885d1f
Parent Certificate	http://cacerts.digicert.com/GeoTrustEVRSACAG2.crt
CRL	http://crl3.digicert.com/GeoTrustEVRSACAG2.crl http://crl4.digicert.com/GeoTrustEVRSACAG2.crl
OCSP	http://ocsp.digicert.com
Certificate Transparency
Signed Certificate Timestamps	19 Feb 2024 14:32:14 UTC \| Google 'Argon2025h1' log \| Qualified 19 Feb 2024 14:32:14 UTC \| DigiCert Yeti2025 Log \| Qualified 19 Feb 2024 14:32:14 UTC \| DigiCert Nessie2025 Log \| Qualified
Fingerprints
SHA1	ed879ac6e62e728242ad30d9053830347c472f24
SHA256	aafce121f41514e68d09edf487eae61e0299bc9b41514cfcdcbef5e8a5609cdd
SPKI SHA256	6fa18b98b9121961e5bf330b334bcd5c4ea64d6dba4a66ce1f9dcc13c8d57e8d

Analysis

Strong private key

Good. The private key associated with this certificate is secure.

Strong signature algorithm

Good. This certificate uses a strong signature algorithm.

Certificate matches hostname

Good. The provided certificate matches the expected hostnames.

Certificate dates match

Good. The certificate is valid for use at this point of time.

Certificate has not been revoked

Good. This certificate has not been revoked.

Certificate satisfies Apple's CT compliance requirements

Good. This certificate satisfies Apple's CT requirements at present.

Symantec subordinate CA excluded from early expiration

Although the leaf certificate ultimately chains to a Symantec root, it has been issued from an independently-operated subordinate CA that has been excluded from early expiration.

Certificate Chain

Leaf certificate

posteo.de | aafce12
Not After: 21 Feb 2025 23:59:59 UTC (expires in 3 months 17 days)
Authentication: RSA 3072 bits (SHA256withRSA)
View details

Names	posteo.de www.posteo.de lists.posteo.de autoconfig.posteo.de mta-sts.posteo.de api.posteo.de cdn.posteo.de autodiscover.posteo.de
Subject DN	CN=posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE
Subject Key Identifier	69b316ba06f9ffa99789de7dfbeb90808f3ffe61
Serial	ce9a457c6a050a2a55c6ebfeae53d18
Not Before	19 Feb 2024 00:00:00 UTC
Not After	21 Feb 2025 23:59:59 UTC
Validity period	369 days
Key Usage	digitalSignature, keyEncipherment
Extended Key Usage	serverAuth, clientAuth
Must Staple	No
Issuer
Issuer DN	CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Extended Validation (EV)
Authority Key Identifier	keyid:28d2cfee098475ddb5b2b5bf3cd5a0c673885d1f
Parent Certificate	http://cacerts.digicert.com/GeoTrustEVRSACAG2.crt
CRL	http://crl3.digicert.com/GeoTrustEVRSACAG2.crl http://crl4.digicert.com/GeoTrustEVRSACAG2.crl
OCSP	http://ocsp.digicert.com
Certificate Transparency
Signed Certificate Timestamps	19 Feb 2024 14:32:14 UTC \| Google 'Argon2025h1' log \| Qualified 19 Feb 2024 14:32:14 UTC \| DigiCert Yeti2025 Log \| Qualified 19 Feb 2024 14:32:14 UTC \| DigiCert Nessie2025 Log \| Qualified
Fingerprints
SHA1	ed879ac6e62e728242ad30d9053830347c472f24
SHA256	aafce121f41514e68d09edf487eae61e0299bc9b41514cfcdcbef5e8a5609cdd
SPKI SHA256	6fa18b98b9121961e5bf330b334bcd5c4ea64d6dba4a66ce1f9dcc13c8d57e8d

Intermediate certificate

GeoTrust EV RSA CA G2 | 2d140f2
Not After: 02 Jul 2030 12:42:57 UTC (expires in 5 years 7 months)
Authentication: RSA 2048 bits (SHA256withRSA)
View details

Subject DN	CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US
Subject Key Identifier	28d2cfee098475ddb5b2b5bf3cd5a0c673885d1f
Serial	d601262c8a7721a6eab0361e5619580
Not Before	02 Jul 2020 12:42:57 UTC
Not After	02 Jul 2030 12:42:57 UTC
Key Usage	digitalSignature, keyCertSign, cRLSign
Extended Key Usage	serverAuth, clientAuth
Issuer
Issuer DN	CN=DigiCert Global Root G2, OU=www.digicert.com, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Not Applicable
Authority Key Identifier	keyid:4e2254201895e6e36ee60ffafab912ed06178f39
CRL	http://crl3.digicert.com/DigiCertGlobalRootG2.crl http://crl4.digicert.com/DigiCertGlobalRootG2.crl
OCSP	http://ocsp.digicert.com
CA certificate	Yes (pathlen 0)
Fingerprints
SHA1	687d4a4d47014f91217e4a062bbf9d238358943e
SHA256	2d140f20b8a96e2b4d2f1cc5aca5e5a1e7dc56a7491e510906960f38d2d21aef
SPKI SHA256	54751a82af3482c59dbe77c72fffb65d22d9ac0264e08f5df1fc7a37c52f5863

Root certificate

DigiCert Global Root G2 | cb3ccbb
Not After: 15 Jan 2038 12:00:00 UTC (expires in 13 years 2 months)
Authentication: RSA 2048 bits (SHA256withRSA)
View details

Subject DN	CN=DigiCert Global Root G2, OU=www.digicert.com, O=DigiCert Inc, C=US
Subject Key Identifier	4e2254201895e6e36ee60ffafab912ed06178f39
Serial	33af1e6a711a9a0bb2864b11d09fae5
Not Before	01 Aug 2013 12:00:00 UTC
Not After	15 Jan 2038 12:00:00 UTC
Key Usage	digitalSignature, keyCertSign, cRLSign
Issuer
Issuer DN	CN=DigiCert Global Root G2, OU=www.digicert.com, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Self-signed
CA certificate	Yes (pathlen unlimited)
Fingerprints
SHA1	df3c24f9bfd666761b268073fe06d1cc8d4f82a4
SHA256	cb3ccbb76031e5e0138f8dd39a23f9de47ffc35e43c1144cea27d46a5ab1cb5f
SPKI SHA256	8bb593a93be1d0e8a822bb887c547890c3e706aad2dab76254f97fb36b82fc26

Analysis

Certificate chain is correct

Good. This chain contains all the right certificates and in the right order.

SMTP TLS Reporting

SMTP TLS Reporting (RFC 8460), or TLS-RPT for short, describes a reporting mechanism and format by which systems sending email can share statistics and specific information about potential failures with recipient domains. Recipient domains can then use this information to both detect potential attacks and diagnose unintentional misconfigurations. TLS-RPT can be used with DANE or MTA-STS.

Test passed

Everything seems to be well configured. Well done.

TLS-RPT Policy

Location from which we retrieved the policy indicator.Location	_smtp._tls.posteo.de
TLS-RPT standard version used by this policy indicator.Version	TLSRPTv1
Reporting endpoints specified in the policy.Reporting Endpoints	mailto:tlsrpt@posteo.de

Analysis

SMTP TLS-RPT policy valid

Good. Your TLS-RPT policy is valid. SMTP TLS Reporting is a young standard that is not yet widely supported, but support is probably going to increase over time.

HTTP (80)

To observe your HTTP implementation, we submit a request to the homepage of your site on port 80, follow all redirections (even when they take us to other domain names), and record the returned HTTP headers.

Test passed

Everything seems to be well configured. Well done.

URL: http://posteo.de/

1

http://posteo.de/

HTTP/1.1 301 Moved Permanently

server	nginx
date	Mon, 04 Nov 2024 05:25:50 GMT
content-type	text/html
content-length	162
location	https://posteo.de/

2

https://posteo.de/

HTTP/1.1 302 Found

date	Mon, 04 Nov 2024 05:25:50 GMT
server	Apache
cache-control	no-cache, no-store, max-age=0, must-revalidate
pragma	no-cache
expires	Fri, 01 Jan 1990 00:00:00 GMT
set-cookie	_mailservice_session=BAh7BzoPc2Vzc2lvbl9pZCIlMDkxYjIzNzYzYjg5OGFlMWI1NmE5ZTc4MGEwNmNhNmE6D2V4cGlyZXNfYXRsKwderCln--7d9a3ed6954308f70a089c47f18128cfa16ba173; path=/; HttpOnly; SameSite=Lax; secure
x-frame-options	SAMEORIGIN
frame-options	SAMEORIGIN
referrer-policy	no-referrer
content-length	86
status	302 Found
x-content-type-options	nosniff
content-security-policy	connect-src https://api.posteo.de https://payment.posteo.de https://cdn.posteo.de wss://posteo.de 'self'; child-src 'self'; font-src 'self' data:; form-action https://www.paypal.com https://hooks.stripe.com 'self' data:; frame-ancestors 'self'; frame-src 'self' blob:; img-src data: *; manifest-src 'self'; media-src 'self' https://cdn.posteo.de; object-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-eval' 'unsafe-inline'; default-src 'none'; reflected-xss block; referrer no-referrer;
permissions-policy	accelerometer=(), ambient-light-sensor=(), autoplay=(), battery=(), camera=(), cross-origin-isolated=(), display-capture=(), document-domain=(), encrypted-media=(), execution-while-not-rendered=(), execution-while-out-of-viewport=(), fullscreen=(), geolocation=(), gyroscope=(), magnetometer=(), microphone=(), midi=(), navigation-override=(), payment=(), picture-in-picture=(), publickey-credentials-get=(), screen-wake-lock=(), sync-xhr=(), usb=(), web-share=(), xr-spatial-tracking=()
location	https://posteo.de/en
content-type	text/html; charset=utf-8
strict-transport-security	max-age=31536000; includeSubDomains; preload
expect-ct	enforce, max-age=300

3

https://posteo.de/en

HTTP/1.1 200 OK

date	Mon, 04 Nov 2024 05:25:51 GMT
server	Apache
x-frame-options	SAMEORIGIN
frame-options	SAMEORIGIN
referrer-policy	no-referrer
vary	Accept-Encoding
last-modified	Mon, 04 Nov 2024 05:23:25 GMT
etag	"4089-6260f7bea535e"
accept-ranges	bytes
x-content-type-options	nosniff
content-security-policy	connect-src https://api.posteo.de https://payment.posteo.de https://cdn.posteo.de wss://posteo.de 'self'; child-src 'self'; font-src 'self' data:; form-action https://www.paypal.com https://hooks.stripe.com 'self' data:; frame-ancestors 'self'; frame-src 'self' blob:; img-src data: *; manifest-src 'self'; media-src 'self' https://cdn.posteo.de; object-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-eval' 'unsafe-inline'; default-src 'none'; reflected-xss block; referrer no-referrer;
permissions-policy	accelerometer=(), ambient-light-sensor=(), autoplay=(), battery=(), camera=(), cross-origin-isolated=(), display-capture=(), document-domain=(), encrypted-media=(), execution-while-not-rendered=(), execution-while-out-of-viewport=(), fullscreen=(), geolocation=(), gyroscope=(), magnetometer=(), microphone=(), midi=(), navigation-override=(), payment=(), picture-in-picture=(), publickey-credentials-get=(), screen-wake-lock=(), sync-xhr=(), usb=(), web-share=(), xr-spatial-tracking=()
cache-control	max-age=0, must-revalidate
content-type	text/html
strict-transport-security	max-age=31536000; includeSubDomains; preload
expect-ct	enforce, max-age=300

Analysis

HTTP redirects to HTTPS

Good. This plaintext HTTP server redirects to HTTPS.

URL: http://www.posteo.de/

1

http://www.posteo.de/

HTTP/1.1 302 Moved Temporarily

server	nginx
date	Mon, 04 Nov 2024 05:25:51 GMT
content-type	text/html
content-length	138
location	https://www.posteo.de/

2

https://www.posteo.de/

HTTP/1.1 302 Moved Temporarily

server	nginx
date	Mon, 04 Nov 2024 05:25:51 GMT
content-type	text/html
content-length	138
location	https://posteo.de/
strict-transport-security	max-age=31536000; includeSubDomains; preload
expect-ct	enforce, max-age=300

3

https://posteo.de/

HTTP/1.1 302 Found

date	Mon, 04 Nov 2024 05:25:52 GMT
server	Apache
cache-control	no-cache, no-store, max-age=0, must-revalidate
pragma	no-cache
expires	Fri, 01 Jan 1990 00:00:00 GMT
set-cookie	_mailservice_session=BAh7BzoPc2Vzc2lvbl9pZCIlZWU2N2U2ZTcxODM4MzFjYmY4ZTgyYzAyNWM1NjdmYzM6D2V4cGlyZXNfYXRsKwdgrCln--1689fc05646bd20046757b7d4b1447d312a46ca5; path=/; HttpOnly; SameSite=Lax; secure
x-frame-options	SAMEORIGIN
frame-options	SAMEORIGIN
referrer-policy	no-referrer
content-length	86
status	302 Found
x-content-type-options	nosniff
content-security-policy	connect-src https://api.posteo.de https://payment.posteo.de https://cdn.posteo.de wss://posteo.de 'self'; child-src 'self'; font-src 'self' data:; form-action https://www.paypal.com https://hooks.stripe.com 'self' data:; frame-ancestors 'self'; frame-src 'self' blob:; img-src data: *; manifest-src 'self'; media-src 'self' https://cdn.posteo.de; object-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-eval' 'unsafe-inline'; default-src 'none'; reflected-xss block; referrer no-referrer;
permissions-policy	accelerometer=(), ambient-light-sensor=(), autoplay=(), battery=(), camera=(), cross-origin-isolated=(), display-capture=(), document-domain=(), encrypted-media=(), execution-while-not-rendered=(), execution-while-out-of-viewport=(), fullscreen=(), geolocation=(), gyroscope=(), magnetometer=(), microphone=(), midi=(), navigation-override=(), payment=(), picture-in-picture=(), publickey-credentials-get=(), screen-wake-lock=(), sync-xhr=(), usb=(), web-share=(), xr-spatial-tracking=()
location	https://posteo.de/en
content-type	text/html; charset=utf-8
strict-transport-security	max-age=31536000; includeSubDomains; preload
expect-ct	enforce, max-age=300

4

https://posteo.de/en

HTTP/1.1 200 OK

date	Mon, 04 Nov 2024 05:25:52 GMT
server	Apache
x-frame-options	SAMEORIGIN
frame-options	SAMEORIGIN
referrer-policy	no-referrer
vary	Accept-Encoding
last-modified	Mon, 04 Nov 2024 05:23:25 GMT
etag	"4089-6260f7bea535e"
accept-ranges	bytes
x-content-type-options	nosniff
content-security-policy	connect-src https://api.posteo.de https://payment.posteo.de https://cdn.posteo.de wss://posteo.de 'self'; child-src 'self'; font-src 'self' data:; form-action https://www.paypal.com https://hooks.stripe.com 'self' data:; frame-ancestors 'self'; frame-src 'self' blob:; img-src data: *; manifest-src 'self'; media-src 'self' https://cdn.posteo.de; object-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-eval' 'unsafe-inline'; default-src 'none'; reflected-xss block; referrer no-referrer;
permissions-policy	accelerometer=(), ambient-light-sensor=(), autoplay=(), battery=(), camera=(), cross-origin-isolated=(), display-capture=(), document-domain=(), encrypted-media=(), execution-while-not-rendered=(), execution-while-out-of-viewport=(), fullscreen=(), geolocation=(), gyroscope=(), magnetometer=(), microphone=(), midi=(), navigation-override=(), payment=(), picture-in-picture=(), publickey-credentials-get=(), screen-wake-lock=(), sync-xhr=(), usb=(), web-share=(), xr-spatial-tracking=()
cache-control	max-age=0, must-revalidate
content-type	text/html
strict-transport-security	max-age=31536000; includeSubDomains; preload
expect-ct	enforce, max-age=300

Analysis

HTTP redirects to HTTPS

Good. This plaintext HTTP server redirects to HTTPS.

HTTP (443)

To observe your HTTPS implementation, we submit a request to the homepage of your site on port 443, follow all redirections (even when they take us to other domain names), and record the returned HTTP headers. We use the most recent set of headers returned from the tested hostname for further tests such as HSTS and HPKP.

Test passed

Everything seems to be well configured. Well done.

URL: https://posteo.de/

1

https://posteo.de/

HTTP/1.1 302 Found

date	Mon, 04 Nov 2024 05:25:53 GMT
server	Apache
cache-control	no-cache, no-store, max-age=0, must-revalidate
pragma	no-cache
expires	Fri, 01 Jan 1990 00:00:00 GMT
set-cookie	_mailservice_session=BAh7BzoPc2Vzc2lvbl9pZCIlOGY4MjM2ZWFiNzk0ODU3MTM1MTBmZWQzNDFlMDdlYTg6D2V4cGlyZXNfYXRsKwdhrCln--a234c5b1ee0f6fedc091e08923307e63fac928bd; path=/; HttpOnly; SameSite=Lax; secure
x-frame-options	SAMEORIGIN
frame-options	SAMEORIGIN
referrer-policy	no-referrer
content-length	86
status	302 Found
x-content-type-options	nosniff
content-security-policy	connect-src https://api.posteo.de https://payment.posteo.de https://cdn.posteo.de wss://posteo.de 'self'; child-src 'self'; font-src 'self' data:; form-action https://www.paypal.com https://hooks.stripe.com 'self' data:; frame-ancestors 'self'; frame-src 'self' blob:; img-src data: *; manifest-src 'self'; media-src 'self' https://cdn.posteo.de; object-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-eval' 'unsafe-inline'; default-src 'none'; reflected-xss block; referrer no-referrer;
permissions-policy	accelerometer=(), ambient-light-sensor=(), autoplay=(), battery=(), camera=(), cross-origin-isolated=(), display-capture=(), document-domain=(), encrypted-media=(), execution-while-not-rendered=(), execution-while-out-of-viewport=(), fullscreen=(), geolocation=(), gyroscope=(), magnetometer=(), microphone=(), midi=(), navigation-override=(), payment=(), picture-in-picture=(), publickey-credentials-get=(), screen-wake-lock=(), sync-xhr=(), usb=(), web-share=(), xr-spatial-tracking=()
location	https://posteo.de/en
content-type	text/html; charset=utf-8
strict-transport-security	max-age=31536000; includeSubDomains; preload
expect-ct	enforce, max-age=300

2

https://posteo.de/en

HTTP/1.1 200 OK

date	Mon, 04 Nov 2024 05:25:53 GMT
server	Apache
x-frame-options	SAMEORIGIN
frame-options	SAMEORIGIN
referrer-policy	no-referrer
vary	Accept-Encoding
last-modified	Mon, 04 Nov 2024 05:23:25 GMT
etag	"4089-6260f7bea535e"
accept-ranges	bytes
x-content-type-options	nosniff
content-security-policy	connect-src https://api.posteo.de https://payment.posteo.de https://cdn.posteo.de wss://posteo.de 'self'; child-src 'self'; font-src 'self' data:; form-action https://www.paypal.com https://hooks.stripe.com 'self' data:; frame-ancestors 'self'; frame-src 'self' blob:; img-src data: *; manifest-src 'self'; media-src 'self' https://cdn.posteo.de; object-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-eval' 'unsafe-inline'; default-src 'none'; reflected-xss block; referrer no-referrer;
permissions-policy	accelerometer=(), ambient-light-sensor=(), autoplay=(), battery=(), camera=(), cross-origin-isolated=(), display-capture=(), document-domain=(), encrypted-media=(), execution-while-not-rendered=(), execution-while-out-of-viewport=(), fullscreen=(), geolocation=(), gyroscope=(), magnetometer=(), microphone=(), midi=(), navigation-override=(), payment=(), picture-in-picture=(), publickey-credentials-get=(), screen-wake-lock=(), sync-xhr=(), usb=(), web-share=(), xr-spatial-tracking=()
cache-control	max-age=0, must-revalidate
content-type	text/html
strict-transport-security	max-age=31536000; includeSubDomains; preload
expect-ct	enforce, max-age=300

URL: https://www.posteo.de/

1

https://www.posteo.de/

HTTP/1.1 302 Moved Temporarily

server	nginx
date	Mon, 04 Nov 2024 05:25:54 GMT
content-type	text/html
content-length	138
location	https://posteo.de/
strict-transport-security	max-age=31536000; includeSubDomains; preload
expect-ct	enforce, max-age=300

2

https://posteo.de/

HTTP/1.1 302 Found

date	Mon, 04 Nov 2024 05:25:54 GMT
server	Apache
cache-control	no-cache, no-store, max-age=0, must-revalidate
pragma	no-cache
expires	Fri, 01 Jan 1990 00:00:00 GMT
set-cookie	_mailservice_session=BAh7BzoPc2Vzc2lvbl9pZCIlMGMyYjY1ZjA1NzRkZTc4YTg5MmRiMjc3Y2MyYjY5YTQ6D2V4cGlyZXNfYXRsKwdirCln--98d915d87d39d02feeb499fc7aa5d39382a183f0; path=/; HttpOnly; SameSite=Lax; secure
x-frame-options	SAMEORIGIN
frame-options	SAMEORIGIN
referrer-policy	no-referrer
content-length	86
status	302 Found
x-content-type-options	nosniff
content-security-policy	connect-src https://api.posteo.de https://payment.posteo.de https://cdn.posteo.de wss://posteo.de 'self'; child-src 'self'; font-src 'self' data:; form-action https://www.paypal.com https://hooks.stripe.com 'self' data:; frame-ancestors 'self'; frame-src 'self' blob:; img-src data: *; manifest-src 'self'; media-src 'self' https://cdn.posteo.de; object-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-eval' 'unsafe-inline'; default-src 'none'; reflected-xss block; referrer no-referrer;
permissions-policy	accelerometer=(), ambient-light-sensor=(), autoplay=(), battery=(), camera=(), cross-origin-isolated=(), display-capture=(), document-domain=(), encrypted-media=(), execution-while-not-rendered=(), execution-while-out-of-viewport=(), fullscreen=(), geolocation=(), gyroscope=(), magnetometer=(), microphone=(), midi=(), navigation-override=(), payment=(), picture-in-picture=(), publickey-credentials-get=(), screen-wake-lock=(), sync-xhr=(), usb=(), web-share=(), xr-spatial-tracking=()
location	https://posteo.de/en
content-type	text/html; charset=utf-8
strict-transport-security	max-age=31536000; includeSubDomains; preload
expect-ct	enforce, max-age=300

3

https://posteo.de/en

HTTP/1.1 200 OK

date	Mon, 04 Nov 2024 05:25:55 GMT
server	Apache
x-frame-options	SAMEORIGIN
frame-options	SAMEORIGIN
referrer-policy	no-referrer
vary	Accept-Encoding
last-modified	Mon, 04 Nov 2024 05:23:25 GMT
etag	"4089-6260f7bea535e"
accept-ranges	bytes
x-content-type-options	nosniff
content-security-policy	connect-src https://api.posteo.de https://payment.posteo.de https://cdn.posteo.de wss://posteo.de 'self'; child-src 'self'; font-src 'self' data:; form-action https://www.paypal.com https://hooks.stripe.com 'self' data:; frame-ancestors 'self'; frame-src 'self' blob:; img-src data: *; manifest-src 'self'; media-src 'self' https://cdn.posteo.de; object-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-eval' 'unsafe-inline'; default-src 'none'; reflected-xss block; referrer no-referrer;
permissions-policy	accelerometer=(), ambient-light-sensor=(), autoplay=(), battery=(), camera=(), cross-origin-isolated=(), display-capture=(), document-domain=(), encrypted-media=(), execution-while-not-rendered=(), execution-while-out-of-viewport=(), fullscreen=(), geolocation=(), gyroscope=(), magnetometer=(), microphone=(), midi=(), navigation-override=(), payment=(), picture-in-picture=(), publickey-credentials-get=(), screen-wake-lock=(), sync-xhr=(), usb=(), web-share=(), xr-spatial-tracking=()
cache-control	max-age=0, must-revalidate
content-type	text/html
strict-transport-security	max-age=31536000; includeSubDomains; preload
expect-ct	enforce, max-age=300

WWW TLS

Transport Layer Security (TLS) is the most widely used encryption protocol on the Internet. In combination with valid certificates, servers can establish trusted communication channels even with users who have never visited them before. Network attackers can't uncover what is being communicated, even when they can see all the traffic.

Test passed

Everything seems to be well configured. Well done.

TLS Configuration: posteo.de (2a05:bc0:1000:0:0:0:169:1)

Encryption protocol version determines what features are available for negotiation between client and server.Supported protocols	TLS v1.3 TLS v1.2
Servers should always enforce their own cipher suite preference, as that is the only approach that guarantees that the best possible suite is selected.Server suite preference
Shows cipher suite configuration for this protocol version.TLS v1.3 Server preference	Suite: TLS_CHACHA20_POLY1305_SHA256 Suite ID: 0x1303 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_AES_256_GCM_SHA384 Suite ID: 0x1302 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_AES_128_GCM_SHA256 Suite ID: 0x1301 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits)
Shows cipher suite configuration for this protocol version.TLS v1.2 Server preference	Suite: TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 Suite ID: 0xcca8 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 Suite ID: 0xc030 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 Suite ID: 0xc02f Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 Suite ID: 0xc028 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 Suite ID: 0xc027 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA Suite ID: 0xc014 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA Suite ID: 0xc013 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA 128 bits (ECDHE 256 bits)

Analysis

TLS 1.3 supported

Excellent. This server supports TLS 1.3, which is the latest revision of the TLS protocol and a significant improvement over earlier versions. Developed over a period of several years and extensively analyzed prior to the release, TLS 1.3 removed insecure features, and improved both security and performance.

TLS 1.2 supported

Good. This server supports TLS 1.2, which can provide strong security when configured correctly. This version of the TLS protocol is necessary to provide good security with a wide range of clients that don't yet support TLS 1.3.

Deprecated protocols not supported

Excellent. This server doesn't support any of the deprecated protocol (TLS 1.1 and earlier).

Strong key exchange detected

Excellent. All cipher suites on this server rely on strong key exchange. The sweet spot is 2048 bits for DHE and 256 bits for ECDHE. Putting ECDHE suites first guarantees best security and best performance.

Server prefers forward secrecy and authenticated encryption suites

Excellent. Not only does this server enforce its server preference, but it also has at the top of the list suites that support both forward secrecy and authenticated encryption. This is the best TLS 1.2 can offer.

Server enforces cipher suite preferences

Excellent. This server enforces server cipher suite preference, which means that it is able to select the best suite from the options submitted by clients. Combined with a well-designed list of supported cipher suites, this setting enables negotiation of best security.

All TLS connections with this server satisfy Apple's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

All TLS connections with this server satisfy Chrome's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

DHE suites not supported

This server doesn't support the Diffie-Hellman (DH) key exchange.

TLS Configuration: posteo.de (185.67.36.168)

Encryption protocol version determines what features are available for negotiation between client and server.Supported protocols	TLS v1.3 TLS v1.2
Servers should always enforce their own cipher suite preference, as that is the only approach that guarantees that the best possible suite is selected.Server suite preference
Shows cipher suite configuration for this protocol version.TLS v1.3 Server preference	Suite: TLS_CHACHA20_POLY1305_SHA256 Suite ID: 0x1303 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_AES_256_GCM_SHA384 Suite ID: 0x1302 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_AES_128_GCM_SHA256 Suite ID: 0x1301 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits)
Shows cipher suite configuration for this protocol version.TLS v1.2 Server preference	Suite: TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 Suite ID: 0xcca8 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 Suite ID: 0xc030 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 Suite ID: 0xc02f Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 Suite ID: 0xc028 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 Suite ID: 0xc027 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA Suite ID: 0xc014 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA Suite ID: 0xc013 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA 128 bits (ECDHE 256 bits)

Analysis

TLS 1.3 supported

Excellent. This server supports TLS 1.3, which is the latest revision of the TLS protocol and a significant improvement over earlier versions. Developed over a period of several years and extensively analyzed prior to the release, TLS 1.3 removed insecure features, and improved both security and performance.

TLS 1.2 supported

Good. This server supports TLS 1.2, which can provide strong security when configured correctly. This version of the TLS protocol is necessary to provide good security with a wide range of clients that don't yet support TLS 1.3.

Deprecated protocols not supported

Excellent. This server doesn't support any of the deprecated protocol (TLS 1.1 and earlier).

Strong key exchange detected

Excellent. All cipher suites on this server rely on strong key exchange. The sweet spot is 2048 bits for DHE and 256 bits for ECDHE. Putting ECDHE suites first guarantees best security and best performance.

Server prefers forward secrecy and authenticated encryption suites

Excellent. Not only does this server enforce its server preference, but it also has at the top of the list suites that support both forward secrecy and authenticated encryption. This is the best TLS 1.2 can offer.

Server enforces cipher suite preferences

Excellent. This server enforces server cipher suite preference, which means that it is able to select the best suite from the options submitted by clients. Combined with a well-designed list of supported cipher suites, this setting enables negotiation of best security.

All TLS connections with this server satisfy Apple's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

All TLS connections with this server satisfy Chrome's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

DHE suites not supported

This server doesn't support the Diffie-Hellman (DH) key exchange.

TLS Configuration: posteo.de (2a05:bc0:1000:0:0:0:168:1)

Encryption protocol version determines what features are available for negotiation between client and server.Supported protocols	TLS v1.3 TLS v1.2
Servers should always enforce their own cipher suite preference, as that is the only approach that guarantees that the best possible suite is selected.Server suite preference
Shows cipher suite configuration for this protocol version.TLS v1.3 Server preference	Suite: TLS_CHACHA20_POLY1305_SHA256 Suite ID: 0x1303 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_AES_256_GCM_SHA384 Suite ID: 0x1302 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_AES_128_GCM_SHA256 Suite ID: 0x1301 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits)
Shows cipher suite configuration for this protocol version.TLS v1.2 Server preference	Suite: TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 Suite ID: 0xcca8 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 Suite ID: 0xc030 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 Suite ID: 0xc02f Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 Suite ID: 0xc028 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 Suite ID: 0xc027 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA Suite ID: 0xc014 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA Suite ID: 0xc013 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA 128 bits (ECDHE 256 bits)

Analysis

TLS 1.3 supported

Excellent. This server supports TLS 1.3, which is the latest revision of the TLS protocol and a significant improvement over earlier versions. Developed over a period of several years and extensively analyzed prior to the release, TLS 1.3 removed insecure features, and improved both security and performance.

TLS 1.2 supported

Good. This server supports TLS 1.2, which can provide strong security when configured correctly. This version of the TLS protocol is necessary to provide good security with a wide range of clients that don't yet support TLS 1.3.

Deprecated protocols not supported

Excellent. This server doesn't support any of the deprecated protocol (TLS 1.1 and earlier).

Strong key exchange detected

Excellent. All cipher suites on this server rely on strong key exchange. The sweet spot is 2048 bits for DHE and 256 bits for ECDHE. Putting ECDHE suites first guarantees best security and best performance.

Server prefers forward secrecy and authenticated encryption suites

Excellent. Not only does this server enforce its server preference, but it also has at the top of the list suites that support both forward secrecy and authenticated encryption. This is the best TLS 1.2 can offer.

Server enforces cipher suite preferences

Excellent. This server enforces server cipher suite preference, which means that it is able to select the best suite from the options submitted by clients. Combined with a well-designed list of supported cipher suites, this setting enables negotiation of best security.

All TLS connections with this server satisfy Apple's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

All TLS connections with this server satisfy Chrome's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

DHE suites not supported

This server doesn't support the Diffie-Hellman (DH) key exchange.

TLS Configuration: posteo.de (185.67.36.169)

Encryption protocol version determines what features are available for negotiation between client and server.Supported protocols	TLS v1.3 TLS v1.2
Servers should always enforce their own cipher suite preference, as that is the only approach that guarantees that the best possible suite is selected.Server suite preference
Shows cipher suite configuration for this protocol version.TLS v1.3 Server preference	Suite: TLS_CHACHA20_POLY1305_SHA256 Suite ID: 0x1303 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_AES_256_GCM_SHA384 Suite ID: 0x1302 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_AES_128_GCM_SHA256 Suite ID: 0x1301 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits)
Shows cipher suite configuration for this protocol version.TLS v1.2 Server preference	Suite: TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 Suite ID: 0xcca8 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 Suite ID: 0xc030 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 Suite ID: 0xc02f Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 Suite ID: 0xc028 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 Suite ID: 0xc027 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA Suite ID: 0xc014 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA Suite ID: 0xc013 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA 128 bits (ECDHE 256 bits)

Analysis

TLS 1.3 supported

Excellent. This server supports TLS 1.3, which is the latest revision of the TLS protocol and a significant improvement over earlier versions. Developed over a period of several years and extensively analyzed prior to the release, TLS 1.3 removed insecure features, and improved both security and performance.

TLS 1.2 supported

Good. This server supports TLS 1.2, which can provide strong security when configured correctly. This version of the TLS protocol is necessary to provide good security with a wide range of clients that don't yet support TLS 1.3.

Deprecated protocols not supported

Excellent. This server doesn't support any of the deprecated protocol (TLS 1.1 and earlier).

Strong key exchange detected

Excellent. All cipher suites on this server rely on strong key exchange. The sweet spot is 2048 bits for DHE and 256 bits for ECDHE. Putting ECDHE suites first guarantees best security and best performance.

Server prefers forward secrecy and authenticated encryption suites

Excellent. Not only does this server enforce its server preference, but it also has at the top of the list suites that support both forward secrecy and authenticated encryption. This is the best TLS 1.2 can offer.

Server enforces cipher suite preferences

Excellent. This server enforces server cipher suite preference, which means that it is able to select the best suite from the options submitted by clients. Combined with a well-designed list of supported cipher suites, this setting enables negotiation of best security.

All TLS connections with this server satisfy Apple's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

All TLS connections with this server satisfy Chrome's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

DHE suites not supported

This server doesn't support the Diffie-Hellman (DH) key exchange.

TLS Configuration: www.posteo.de (2a05:bc0:1000:0:0:0:169:1)

Encryption protocol version determines what features are available for negotiation between client and server.Supported protocols	TLS v1.3 TLS v1.2
Servers should always enforce their own cipher suite preference, as that is the only approach that guarantees that the best possible suite is selected.Server suite preference
Shows cipher suite configuration for this protocol version.TLS v1.3 Server preference	Suite: TLS_CHACHA20_POLY1305_SHA256 Suite ID: 0x1303 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_AES_256_GCM_SHA384 Suite ID: 0x1302 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_AES_128_GCM_SHA256 Suite ID: 0x1301 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits)
Shows cipher suite configuration for this protocol version.TLS v1.2 Server preference	Suite: TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 Suite ID: 0xcca8 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 Suite ID: 0xc030 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 Suite ID: 0xc02f Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 Suite ID: 0xc028 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 Suite ID: 0xc027 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA Suite ID: 0xc014 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA Suite ID: 0xc013 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA 128 bits (ECDHE 256 bits)

Analysis

TLS 1.3 supported

Excellent. This server supports TLS 1.3, which is the latest revision of the TLS protocol and a significant improvement over earlier versions. Developed over a period of several years and extensively analyzed prior to the release, TLS 1.3 removed insecure features, and improved both security and performance.

TLS 1.2 supported

Good. This server supports TLS 1.2, which can provide strong security when configured correctly. This version of the TLS protocol is necessary to provide good security with a wide range of clients that don't yet support TLS 1.3.

Deprecated protocols not supported

Excellent. This server doesn't support any of the deprecated protocol (TLS 1.1 and earlier).

Strong key exchange detected

Excellent. All cipher suites on this server rely on strong key exchange. The sweet spot is 2048 bits for DHE and 256 bits for ECDHE. Putting ECDHE suites first guarantees best security and best performance.

Server prefers forward secrecy and authenticated encryption suites

Excellent. Not only does this server enforce its server preference, but it also has at the top of the list suites that support both forward secrecy and authenticated encryption. This is the best TLS 1.2 can offer.

Server enforces cipher suite preferences

Excellent. This server enforces server cipher suite preference, which means that it is able to select the best suite from the options submitted by clients. Combined with a well-designed list of supported cipher suites, this setting enables negotiation of best security.

All TLS connections with this server satisfy Apple's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

All TLS connections with this server satisfy Chrome's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

DHE suites not supported

This server doesn't support the Diffie-Hellman (DH) key exchange.

TLS Configuration: www.posteo.de (185.67.36.168)

Encryption protocol version determines what features are available for negotiation between client and server.Supported protocols	TLS v1.3 TLS v1.2
Servers should always enforce their own cipher suite preference, as that is the only approach that guarantees that the best possible suite is selected.Server suite preference
Shows cipher suite configuration for this protocol version.TLS v1.3 Server preference	Suite: TLS_CHACHA20_POLY1305_SHA256 Suite ID: 0x1303 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_AES_256_GCM_SHA384 Suite ID: 0x1302 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_AES_128_GCM_SHA256 Suite ID: 0x1301 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits)
Shows cipher suite configuration for this protocol version.TLS v1.2 Server preference	Suite: TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 Suite ID: 0xcca8 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 Suite ID: 0xc030 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 Suite ID: 0xc02f Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 Suite ID: 0xc028 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 Suite ID: 0xc027 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA Suite ID: 0xc014 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA Suite ID: 0xc013 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA 128 bits (ECDHE 256 bits)

Analysis

TLS 1.3 supported

Excellent. This server supports TLS 1.3, which is the latest revision of the TLS protocol and a significant improvement over earlier versions. Developed over a period of several years and extensively analyzed prior to the release, TLS 1.3 removed insecure features, and improved both security and performance.

TLS 1.2 supported

Good. This server supports TLS 1.2, which can provide strong security when configured correctly. This version of the TLS protocol is necessary to provide good security with a wide range of clients that don't yet support TLS 1.3.

Deprecated protocols not supported

Excellent. This server doesn't support any of the deprecated protocol (TLS 1.1 and earlier).

Strong key exchange detected

Excellent. All cipher suites on this server rely on strong key exchange. The sweet spot is 2048 bits for DHE and 256 bits for ECDHE. Putting ECDHE suites first guarantees best security and best performance.

Server prefers forward secrecy and authenticated encryption suites

Excellent. Not only does this server enforce its server preference, but it also has at the top of the list suites that support both forward secrecy and authenticated encryption. This is the best TLS 1.2 can offer.

Server enforces cipher suite preferences

Excellent. This server enforces server cipher suite preference, which means that it is able to select the best suite from the options submitted by clients. Combined with a well-designed list of supported cipher suites, this setting enables negotiation of best security.

All TLS connections with this server satisfy Apple's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

All TLS connections with this server satisfy Chrome's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

DHE suites not supported

This server doesn't support the Diffie-Hellman (DH) key exchange.

TLS Configuration: www.posteo.de (2a05:bc0:1000:0:0:0:168:1)

Encryption protocol version determines what features are available for negotiation between client and server.Supported protocols	TLS v1.3 TLS v1.2
Servers should always enforce their own cipher suite preference, as that is the only approach that guarantees that the best possible suite is selected.Server suite preference
Shows cipher suite configuration for this protocol version.TLS v1.3 Server preference	Suite: TLS_CHACHA20_POLY1305_SHA256 Suite ID: 0x1303 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_AES_256_GCM_SHA384 Suite ID: 0x1302 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_AES_128_GCM_SHA256 Suite ID: 0x1301 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits)
Shows cipher suite configuration for this protocol version.TLS v1.2 Server preference	Suite: TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 Suite ID: 0xcca8 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 Suite ID: 0xc030 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 Suite ID: 0xc02f Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 Suite ID: 0xc028 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 Suite ID: 0xc027 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA Suite ID: 0xc014 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA Suite ID: 0xc013 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA 128 bits (ECDHE 256 bits)

Analysis

TLS 1.3 supported

Excellent. This server supports TLS 1.3, which is the latest revision of the TLS protocol and a significant improvement over earlier versions. Developed over a period of several years and extensively analyzed prior to the release, TLS 1.3 removed insecure features, and improved both security and performance.

TLS 1.2 supported

Good. This server supports TLS 1.2, which can provide strong security when configured correctly. This version of the TLS protocol is necessary to provide good security with a wide range of clients that don't yet support TLS 1.3.

Deprecated protocols not supported

Excellent. This server doesn't support any of the deprecated protocol (TLS 1.1 and earlier).

Strong key exchange detected

Excellent. All cipher suites on this server rely on strong key exchange. The sweet spot is 2048 bits for DHE and 256 bits for ECDHE. Putting ECDHE suites first guarantees best security and best performance.

Server prefers forward secrecy and authenticated encryption suites

Excellent. Not only does this server enforce its server preference, but it also has at the top of the list suites that support both forward secrecy and authenticated encryption. This is the best TLS 1.2 can offer.

Server enforces cipher suite preferences

Excellent. This server enforces server cipher suite preference, which means that it is able to select the best suite from the options submitted by clients. Combined with a well-designed list of supported cipher suites, this setting enables negotiation of best security.

All TLS connections with this server satisfy Apple's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

All TLS connections with this server satisfy Chrome's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

DHE suites not supported

This server doesn't support the Diffie-Hellman (DH) key exchange.

TLS Configuration: www.posteo.de (185.67.36.169)

Encryption protocol version determines what features are available for negotiation between client and server.Supported protocols	TLS v1.3 TLS v1.2
Servers should always enforce their own cipher suite preference, as that is the only approach that guarantees that the best possible suite is selected.Server suite preference
Shows cipher suite configuration for this protocol version.TLS v1.3 Server preference	Suite: TLS_CHACHA20_POLY1305_SHA256 Suite ID: 0x1303 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_AES_256_GCM_SHA384 Suite ID: 0x1302 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_AES_128_GCM_SHA256 Suite ID: 0x1301 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ecdh_x25519 Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits)
Shows cipher suite configuration for this protocol version.TLS v1.2 Server preference	Suite: TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 Suite ID: 0xcca8 Cipher name: CHACHA20 Cipher strength: 256 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 Suite ID: 0xc030 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 Suite ID: 0xc02f Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: AEAD Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 Suite ID: 0xc028 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA384 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 Suite ID: 0xc027 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA256 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 128 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA Suite ID: 0xc014 Cipher name: AES Cipher strength: 256 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA 256 bits (ECDHE 256 bits) Suite: TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA Suite ID: 0xc013 Cipher name: AES Cipher strength: 128 bits Cipher block size: 128 bits Cipher mode: CBC Key exchange: ECDHE_RSA Key exchange strength: EC ecdh_x25519 (256 bits) Forward secrecy: Yes PRF: SHA TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA 128 bits (ECDHE 256 bits)

Analysis

TLS 1.3 supported

Excellent. This server supports TLS 1.3, which is the latest revision of the TLS protocol and a significant improvement over earlier versions. Developed over a period of several years and extensively analyzed prior to the release, TLS 1.3 removed insecure features, and improved both security and performance.

TLS 1.2 supported

Good. This server supports TLS 1.2, which can provide strong security when configured correctly. This version of the TLS protocol is necessary to provide good security with a wide range of clients that don't yet support TLS 1.3.

Deprecated protocols not supported

Excellent. This server doesn't support any of the deprecated protocol (TLS 1.1 and earlier).

Strong key exchange detected

Excellent. All cipher suites on this server rely on strong key exchange. The sweet spot is 2048 bits for DHE and 256 bits for ECDHE. Putting ECDHE suites first guarantees best security and best performance.

Server prefers forward secrecy and authenticated encryption suites

Excellent. Not only does this server enforce its server preference, but it also has at the top of the list suites that support both forward secrecy and authenticated encryption. This is the best TLS 1.2 can offer.

Server enforces cipher suite preferences

Excellent. This server enforces server cipher suite preference, which means that it is able to select the best suite from the options submitted by clients. Combined with a well-designed list of supported cipher suites, this setting enables negotiation of best security.

All TLS connections with this server satisfy Apple's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

All TLS connections with this server satisfy Chrome's CT requirements

All TLS connections established with this server satisfy Chrome's CT requirements, using certificate, TLS extension, or OCSP response as SCT transport method.

SCT transports: CERT

DHE suites not supported

This server doesn't support the Diffie-Hellman (DH) key exchange.

WWW Certificates

A certificate is a digital document that contains a public key, some information about the entity associated with it, and a digital signature from the certificate issuer. It’s a mechanism that enables us to exchange, store, and use public keys. Being able to reliably verify the identity of a remote server is crucial in order to achieve secure encrypted communication.

Test passed

Everything seems to be well configured. Well done.

Certificate: www.posteo.de

Leaf certificate

posteo.de
Issuer: DigiCert
Not Before: 19 Feb 2024 00:00:00 UTC
Not After: 21 Feb 2025 23:59:59 UTC (expires in 3 months 17 days)
Key: RSA 3072 bits
Signature: SHA256withRSA
View details

Names	posteo.de www.posteo.de lists.posteo.de autoconfig.posteo.de mta-sts.posteo.de api.posteo.de cdn.posteo.de autodiscover.posteo.de
Subject DN	CN=posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE
Subject Key Identifier	69b316ba06f9ffa99789de7dfbeb90808f3ffe61
Serial	ce9a457c6a050a2a55c6ebfeae53d18
Not Before	19 Feb 2024 00:00:00 UTC
Not After	21 Feb 2025 23:59:59 UTC
Validity period	369 days
Key Usage	digitalSignature, keyEncipherment
Extended Key Usage	serverAuth, clientAuth
Must Staple	No
Issuer
Issuer DN	CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Extended Validation (EV)
Authority Key Identifier	keyid:28d2cfee098475ddb5b2b5bf3cd5a0c673885d1f
Parent Certificate	http://cacerts.digicert.com/GeoTrustEVRSACAG2.crt
CRL	http://crl3.digicert.com/GeoTrustEVRSACAG2.crl http://crl4.digicert.com/GeoTrustEVRSACAG2.crl
OCSP	http://ocsp.digicert.com
Certificate Transparency
Signed Certificate Timestamps	19 Feb 2024 14:32:14 UTC \| Google 'Argon2025h1' log \| Qualified 19 Feb 2024 14:32:14 UTC \| DigiCert Yeti2025 Log \| Qualified 19 Feb 2024 14:32:14 UTC \| DigiCert Nessie2025 Log \| Qualified
Fingerprints
SHA1	ed879ac6e62e728242ad30d9053830347c472f24
SHA256	aafce121f41514e68d09edf487eae61e0299bc9b41514cfcdcbef5e8a5609cdd
SPKI SHA256	6fa18b98b9121961e5bf330b334bcd5c4ea64d6dba4a66ce1f9dcc13c8d57e8d

Analysis

Strong private key

Good. The private key associated with this certificate is secure.

Strong signature algorithm

Good. This certificate uses a strong signature algorithm.

Certificate matches hostname

Good. The provided certificate matches the expected hostnames.

Certificate dates match

Good. The certificate is valid for use at this point of time.

Certificate has not been revoked

Good. This certificate has not been revoked.

Certificate satisfies Apple's CT compliance requirements

Good. This certificate satisfies Apple's CT requirements at present.

Symantec subordinate CA excluded from early expiration

Although the leaf certificate ultimately chains to a Symantec root, it has been issued from an independently-operated subordinate CA that has been excluded from early expiration.

Certificate Trust

Determining whether a certificate is considered valid is a complicated process that depends on the exact configuration of the validating party. For trust to be established, the certificate must form a chain that ends with a trusted root. In this section we evaluate the server's certificate against major root stores.

Platform	Trusted
Apple
Google AOSP
Microsoft
Mozilla

Certificate Chain

For a server certificate to be valid, it must be presented as part of a complete and valid certificate chain. The last certificate in the chain should be the root and is usually not included in the configuration.

Leaf certificate

posteo.de | aafce12
Not After: 21 Feb 2025 23:59:59 UTC (expires in 3 months 17 days)
Authentication: RSA 3072 bits (SHA256withRSA)
View details

Names	posteo.de www.posteo.de lists.posteo.de autoconfig.posteo.de mta-sts.posteo.de api.posteo.de cdn.posteo.de autodiscover.posteo.de
Subject DN	CN=posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE
Subject Key Identifier	69b316ba06f9ffa99789de7dfbeb90808f3ffe61
Serial	ce9a457c6a050a2a55c6ebfeae53d18
Not Before	19 Feb 2024 00:00:00 UTC
Not After	21 Feb 2025 23:59:59 UTC
Validity period	369 days
Key Usage	digitalSignature, keyEncipherment
Extended Key Usage	serverAuth, clientAuth
Must Staple	No
Issuer
Issuer DN	CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Extended Validation (EV)
Authority Key Identifier	keyid:28d2cfee098475ddb5b2b5bf3cd5a0c673885d1f
Parent Certificate	http://cacerts.digicert.com/GeoTrustEVRSACAG2.crt
CRL	http://crl3.digicert.com/GeoTrustEVRSACAG2.crl http://crl4.digicert.com/GeoTrustEVRSACAG2.crl
OCSP	http://ocsp.digicert.com
Certificate Transparency
Signed Certificate Timestamps	19 Feb 2024 14:32:14 UTC \| Google 'Argon2025h1' log \| Qualified 19 Feb 2024 14:32:14 UTC \| DigiCert Yeti2025 Log \| Qualified 19 Feb 2024 14:32:14 UTC \| DigiCert Nessie2025 Log \| Qualified
Fingerprints
SHA1	ed879ac6e62e728242ad30d9053830347c472f24
SHA256	aafce121f41514e68d09edf487eae61e0299bc9b41514cfcdcbef5e8a5609cdd
SPKI SHA256	6fa18b98b9121961e5bf330b334bcd5c4ea64d6dba4a66ce1f9dcc13c8d57e8d

Intermediate certificate

GeoTrust EV RSA CA G2 | 2d140f2
Not After: 02 Jul 2030 12:42:57 UTC (expires in 5 years 7 months)
Authentication: RSA 2048 bits (SHA256withRSA)
View details

Subject DN	CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US
Subject Key Identifier	28d2cfee098475ddb5b2b5bf3cd5a0c673885d1f
Serial	d601262c8a7721a6eab0361e5619580
Not Before	02 Jul 2020 12:42:57 UTC
Not After	02 Jul 2030 12:42:57 UTC
Key Usage	digitalSignature, keyCertSign, cRLSign
Extended Key Usage	serverAuth, clientAuth
Issuer
Issuer DN	CN=DigiCert Global Root G2, OU=www.digicert.com, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Not Applicable
Authority Key Identifier	keyid:4e2254201895e6e36ee60ffafab912ed06178f39
CRL	http://crl3.digicert.com/DigiCertGlobalRootG2.crl http://crl4.digicert.com/DigiCertGlobalRootG2.crl
OCSP	http://ocsp.digicert.com
CA certificate	Yes (pathlen 0)
Fingerprints
SHA1	687d4a4d47014f91217e4a062bbf9d238358943e
SHA256	2d140f20b8a96e2b4d2f1cc5aca5e5a1e7dc56a7491e510906960f38d2d21aef
SPKI SHA256	54751a82af3482c59dbe77c72fffb65d22d9ac0264e08f5df1fc7a37c52f5863

Root certificate

DigiCert Global Root G2 | cb3ccbb
Not After: 15 Jan 2038 12:00:00 UTC (expires in 13 years 2 months)
Authentication: RSA 2048 bits (SHA256withRSA)
View details

Subject DN	CN=DigiCert Global Root G2, OU=www.digicert.com, O=DigiCert Inc, C=US
Subject Key Identifier	4e2254201895e6e36ee60ffafab912ed06178f39
Serial	33af1e6a711a9a0bb2864b11d09fae5
Not Before	01 Aug 2013 12:00:00 UTC
Not After	15 Jan 2038 12:00:00 UTC
Key Usage	digitalSignature, keyCertSign, cRLSign
Issuer
Issuer DN	CN=DigiCert Global Root G2, OU=www.digicert.com, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Self-signed
CA certificate	Yes (pathlen unlimited)
Fingerprints
SHA1	df3c24f9bfd666761b268073fe06d1cc8d4f82a4
SHA256	cb3ccbb76031e5e0138f8dd39a23f9de47ffc35e43c1144cea27d46a5ab1cb5f
SPKI SHA256	8bb593a93be1d0e8a822bb887c547890c3e706aad2dab76254f97fb36b82fc26

Analysis

Certificate chain is correct

Good. This chain contains all the right certificates and in the right order.

Certificate: posteo.de

Leaf certificate

posteo.de
Issuer: DigiCert
Not Before: 19 Feb 2024 00:00:00 UTC
Not After: 21 Feb 2025 23:59:59 UTC (expires in 3 months 17 days)
Key: RSA 3072 bits
Signature: SHA256withRSA
View details

Names	posteo.de www.posteo.de lists.posteo.de autoconfig.posteo.de mta-sts.posteo.de api.posteo.de cdn.posteo.de autodiscover.posteo.de
Subject DN	CN=posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE
Subject Key Identifier	69b316ba06f9ffa99789de7dfbeb90808f3ffe61
Serial	ce9a457c6a050a2a55c6ebfeae53d18
Not Before	19 Feb 2024 00:00:00 UTC
Not After	21 Feb 2025 23:59:59 UTC
Validity period	369 days
Key Usage	digitalSignature, keyEncipherment
Extended Key Usage	serverAuth, clientAuth
Must Staple	No
Issuer
Issuer DN	CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Extended Validation (EV)
Authority Key Identifier	keyid:28d2cfee098475ddb5b2b5bf3cd5a0c673885d1f
Parent Certificate	http://cacerts.digicert.com/GeoTrustEVRSACAG2.crt
CRL	http://crl3.digicert.com/GeoTrustEVRSACAG2.crl http://crl4.digicert.com/GeoTrustEVRSACAG2.crl
OCSP	http://ocsp.digicert.com
Certificate Transparency
Signed Certificate Timestamps	19 Feb 2024 14:32:14 UTC \| Google 'Argon2025h1' log \| Qualified 19 Feb 2024 14:32:14 UTC \| DigiCert Yeti2025 Log \| Qualified 19 Feb 2024 14:32:14 UTC \| DigiCert Nessie2025 Log \| Qualified
Fingerprints
SHA1	ed879ac6e62e728242ad30d9053830347c472f24
SHA256	aafce121f41514e68d09edf487eae61e0299bc9b41514cfcdcbef5e8a5609cdd
SPKI SHA256	6fa18b98b9121961e5bf330b334bcd5c4ea64d6dba4a66ce1f9dcc13c8d57e8d

Analysis

Strong private key

Good. The private key associated with this certificate is secure.

Strong signature algorithm

Good. This certificate uses a strong signature algorithm.

Certificate matches hostname

Good. The provided certificate matches the expected hostnames.

Certificate dates match

Good. The certificate is valid for use at this point of time.

Certificate has not been revoked

Good. This certificate has not been revoked.

Certificate satisfies Apple's CT compliance requirements

Good. This certificate satisfies Apple's CT requirements at present.

Symantec subordinate CA excluded from early expiration

Although the leaf certificate ultimately chains to a Symantec root, it has been issued from an independently-operated subordinate CA that has been excluded from early expiration.

Certificate Trust

Determining whether a certificate is considered valid is a complicated process that depends on the exact configuration of the validating party. For trust to be established, the certificate must form a chain that ends with a trusted root. In this section we evaluate the server's certificate against major root stores.

Platform	Trusted
Apple
Google AOSP
Microsoft
Mozilla

Certificate Chain

For a server certificate to be valid, it must be presented as part of a complete and valid certificate chain. The last certificate in the chain should be the root and is usually not included in the configuration.

Leaf certificate

posteo.de | aafce12
Not After: 21 Feb 2025 23:59:59 UTC (expires in 3 months 17 days)
Authentication: RSA 3072 bits (SHA256withRSA)
View details

Names	posteo.de www.posteo.de lists.posteo.de autoconfig.posteo.de mta-sts.posteo.de api.posteo.de cdn.posteo.de autodiscover.posteo.de
Subject DN	CN=posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE
Subject Key Identifier	69b316ba06f9ffa99789de7dfbeb90808f3ffe61
Serial	ce9a457c6a050a2a55c6ebfeae53d18
Not Before	19 Feb 2024 00:00:00 UTC
Not After	21 Feb 2025 23:59:59 UTC
Validity period	369 days
Key Usage	digitalSignature, keyEncipherment
Extended Key Usage	serverAuth, clientAuth
Must Staple	No
Issuer
Issuer DN	CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Extended Validation (EV)
Authority Key Identifier	keyid:28d2cfee098475ddb5b2b5bf3cd5a0c673885d1f
Parent Certificate	http://cacerts.digicert.com/GeoTrustEVRSACAG2.crt
CRL	http://crl3.digicert.com/GeoTrustEVRSACAG2.crl http://crl4.digicert.com/GeoTrustEVRSACAG2.crl
OCSP	http://ocsp.digicert.com
Certificate Transparency
Signed Certificate Timestamps	19 Feb 2024 14:32:14 UTC \| Google 'Argon2025h1' log \| Qualified 19 Feb 2024 14:32:14 UTC \| DigiCert Yeti2025 Log \| Qualified 19 Feb 2024 14:32:14 UTC \| DigiCert Nessie2025 Log \| Qualified
Fingerprints
SHA1	ed879ac6e62e728242ad30d9053830347c472f24
SHA256	aafce121f41514e68d09edf487eae61e0299bc9b41514cfcdcbef5e8a5609cdd
SPKI SHA256	6fa18b98b9121961e5bf330b334bcd5c4ea64d6dba4a66ce1f9dcc13c8d57e8d

Intermediate certificate

GeoTrust EV RSA CA G2 | 2d140f2
Not After: 02 Jul 2030 12:42:57 UTC (expires in 5 years 7 months)
Authentication: RSA 2048 bits (SHA256withRSA)
View details

Subject DN	CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US
Subject Key Identifier	28d2cfee098475ddb5b2b5bf3cd5a0c673885d1f
Serial	d601262c8a7721a6eab0361e5619580
Not Before	02 Jul 2020 12:42:57 UTC
Not After	02 Jul 2030 12:42:57 UTC
Key Usage	digitalSignature, keyCertSign, cRLSign
Extended Key Usage	serverAuth, clientAuth
Issuer
Issuer DN	CN=DigiCert Global Root G2, OU=www.digicert.com, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Not Applicable
Authority Key Identifier	keyid:4e2254201895e6e36ee60ffafab912ed06178f39
CRL	http://crl3.digicert.com/DigiCertGlobalRootG2.crl http://crl4.digicert.com/DigiCertGlobalRootG2.crl
OCSP	http://ocsp.digicert.com
CA certificate	Yes (pathlen 0)
Fingerprints
SHA1	687d4a4d47014f91217e4a062bbf9d238358943e
SHA256	2d140f20b8a96e2b4d2f1cc5aca5e5a1e7dc56a7491e510906960f38d2d21aef
SPKI SHA256	54751a82af3482c59dbe77c72fffb65d22d9ac0264e08f5df1fc7a37c52f5863

Root certificate

DigiCert Global Root G2 | cb3ccbb
Not After: 15 Jan 2038 12:00:00 UTC (expires in 13 years 2 months)
Authentication: RSA 2048 bits (SHA256withRSA)
View details

Subject DN	CN=DigiCert Global Root G2, OU=www.digicert.com, O=DigiCert Inc, C=US
Subject Key Identifier	4e2254201895e6e36ee60ffafab912ed06178f39
Serial	33af1e6a711a9a0bb2864b11d09fae5
Not Before	01 Aug 2013 12:00:00 UTC
Not After	15 Jan 2038 12:00:00 UTC
Key Usage	digitalSignature, keyCertSign, cRLSign
Issuer
Issuer DN	CN=DigiCert Global Root G2, OU=www.digicert.com, O=DigiCert Inc, C=US
Certification Authority	DigiCert
Validation Type	Self-signed
CA certificate	Yes (pathlen unlimited)
Fingerprints
SHA1	df3c24f9bfd666761b268073fe06d1cc8d4f82a4
SHA256	cb3ccbb76031e5e0138f8dd39a23f9de47ffc35e43c1144cea27d46a5ab1cb5f
SPKI SHA256	8bb593a93be1d0e8a822bb887c547890c3e706aad2dab76254f97fb36b82fc26

Analysis

Certificate chain is correct

Good. This chain contains all the right certificates and in the right order.

DANE (443)

DNS-based Authentication of Named Entities (DANE) is a bridge between DNSSEC and TLS. In one possible scenario, DANE can be used for public key pinning, building on an existing publicly-trusted certificate. In another approach, it can be used to completely bypass the CA ecosystem and establish trust using DNSSEC alone.

Test passed

Everything seems to be well configured. Well done.

TLSA Record #1: _443._tcp.posteo.de.

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	a321e2aa0b70d81b6fef08e7180c08be7e4ce92d6602df5bf6d3d6d617bf54e0

TLSA Record #2: _443._tcp.posteo.de.

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	604016df5069274948aa519ac9236b70fcf1b455867c97ab856022c8affcc6ea

TLSA Record #3: _443._tcp.posteo.de.

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	6fa18b98b9121961e5bf330b334bcd5c4ea64d6dba4a66ce1f9dcc13c8d57e8d Leaf certificate: RSA 3072 bits Subject: CN=posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE Issuer: CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US posteo.de (RSA 3072 bits)

Analysis

DANE configuration matches

DANE configuration is present for this service and matches the certificate chain.

Valid DANE configuration

Excellent. Your DANE configuration matches the certificate chain(s) provided by the service. Your TLS configuration enjoys the additional benefit of DANE validation.

TLSA Record #4: _443._tcp.www.posteo.de.

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	a321e2aa0b70d81b6fef08e7180c08be7e4ce92d6602df5bf6d3d6d617bf54e0

TLSA Record #5: _443._tcp.www.posteo.de.

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	604016df5069274948aa519ac9236b70fcf1b455867c97ab856022c8affcc6ea

TLSA Record #6: _443._tcp.www.posteo.de.

Specifies which certificate in the chain is being pinned and how validation should be performed.Certificate Usage	Domain-issued certificate / DANE-EE (3)
Determines if the association is made with a certificate or with a public key (via its SPKI structure).Selector	SPKI structure (1)
Determines how matching is done; directly or via a hash. Matching Type	SHA2-256 (1)
Contains the data necessary to perform the matching. Data	6fa18b98b9121961e5bf330b334bcd5c4ea64d6dba4a66ce1f9dcc13c8d57e8d Leaf certificate: RSA 3072 bits Subject: CN=posteo.de, O=Posteo e.K., L=Berlin, ST=Berlin, C=DE, SERIALNUMBER=HRA 47592, OID.2.5.4.15=Private Organization, OID.1.3.6.1.4.1.311.60.2.1.1=Charlottenburg, OID.1.3.6.1.4.1.311.60.2.1.2=Berlin, OID.1.3.6.1.4.1.311.60.2.1.3=DE Issuer: CN=GeoTrust EV RSA CA G2, O=DigiCert Inc, C=US posteo.de (RSA 3072 bits)

Analysis

DANE configuration matches

DANE configuration is present for this service and matches the certificate chain.

Valid DANE configuration

Excellent. Your DANE configuration matches the certificate chain(s) provided by the service. Your TLS configuration enjoys the additional benefit of DANE validation.

Cookies

Cookies are small chunks of text that are sent between your browser and a website. They are often essential to the operation of the site and sometimes contain sensitive information. Session cookies sent from secure sites must be explicitly marked as secure to prevent being obtained by active network attackers.

Test passed

Everything seems to be well configured. Well done.

HTML Content

On virtually all web sites, HTML markup, images, style sheets, JavaScript, and other page resources arrive not only over multiple connections but possibly from multiple servers and sites spread across the entire Internet. For a page to be properly encrypted, it’s necessary that all the content is retrieved over HTTPS. In practice, that’s very often not the case, leading to mixed content security problems.

Test passed

Everything seems to be well configured. Well done.

Encryption of Embedded Resources

In this section we look at the transport security of all embedded resources. Mixed active content occurs when there are unprotected scripts or styles embedded in a page. This is typically not allowed by modern browsers. Mixed passive content (images, videos and such) are typically allowed, but shouldn't be present.

13 script(s)
13 out of 13 are secure View all

Status	Link
Encrypted	https://posteo.de/...avascripts/basics.js
Encrypted	https://posteo.de/...feedback-messages.js
Encrypted	https://posteo.de/...esponsive-nav.min.js
Encrypted	https://posteo.de/...sponsive-nav-init.js
Encrypted	https://posteo.de/...-website-onscroll.js
Encrypted	https://posteo.de/...ts/posteo-website.js
Encrypted	https://posteo.de/...swiper-bundle.min.js
Encrypted	https://posteo.de/...init-stage-slider.js
Encrypted	https://posteo.de/...init-press-slider.js
Encrypted	https://posteo.de/...etectTouchOrMouse.js
Encrypted	https://posteo.de/...ts/ie11-polyfills.js
Encrypted	https://posteo.de/...ssword-visibility.js
Encrypted	https://posteo.de/...-visibility-login.js

4 CSS file(s)
4 out of 4 are secure View all

Status	Link
Encrypted	https://posteo.de/...sword-visibility.css
Encrypted	https://posteo.de/...wiper-bundle.min.css
Encrypted	https://posteo.de/...p_styles-website.css
Encrypted	https://posteo.de/.../p_print_website.css

50 media file(s)
50 out of 50 are secure View all

Status	Link
Encrypted	https://posteo.de/...ages/posteo-logo.svg
Encrypted	https://posteo.de/...g-icons/fa-globe.svg
Encrypted	https://posteo.de/...g-icons/fa-globe.svg
Encrypted	https://posteo.de/...g-icons/fa-globe.svg
Encrypted	https://posteo.de/...g-icons/fa-globe.svg
Encrypted	https://posteo.de/...lider-1-intro_de.png
Encrypted	https://posteo.de/...der-10-themes_de.png
Encrypted	https://posteo.de/...lider-2-email_de.png
Encrypted	https://posteo.de/...er-3-kalender_de.png
Encrypted	https://posteo.de/...-4-adressbuch_de.png
Encrypted	https://posteo.de/...der-5-nachhaltig.png
Encrypted	https://posteo.de/...er-6-datenschutz.png
Encrypted	https://posteo.de/...verschluesselung.png
Encrypted	https://posteo.de/...ider-8-werbefrei.png
Encrypted	https://posteo.de/...-9-umzugsservice.png
Encrypted	https://posteo.de/.../mail_leistungen.png
Encrypted	https://posteo.de/...eenshot_guardian.png
Encrypted	https://posteo.de/...hot_planetwissen.png
Encrypted	https://posteo.de/...screenshot_stiwa.png
Encrypted	https://posteo.de/...screenshot_heise.png
Encrypted	https://posteo.de/...creenshot_dradio.png
Encrypted	https://posteo.de/...r/screenshot_faz.png
Encrypted	https://posteo.de/...eenshot_oekotest.png
Encrypted	https://posteo.de/...screenshot_heise.png
Encrypted	https://posteo.de/...r/screenshot_ard.png
Encrypted	https://posteo.de/...technologyreview.png
Encrypted	https://posteo.de/...technologyreview.png
Encrypted	https://posteo.de/...er/screenshot_ct.png
Encrypted	https://posteo.de/...er/screenshot_ct.png
Encrypted	https://posteo.de/...hot_computerbild.png
Encrypted	https://posteo.de/...hot_tagesspiegel.png
Encrypted	https://posteo.de/...screenshot_linux.png
Encrypted	https://posteo.de/.../screenshot_chip.png
Encrypted	https://posteo.de/...enshot_futurzwei.png
Encrypted	https://posteo.de/...shot_netzpolitik.png
Encrypted	https://posteo.de/.../screenshot_spon.png
Encrypted	https://posteo.de/...er/screenshot_sz.png
Encrypted	https://posteo.de/...er/screenshot_ct.png
Encrypted	https://posteo.de/...nshot_irishtimes.png
Encrypted	https://posteo.de/..._berlinerzeitung.png
Encrypted	https://posteo.de/...reenshot_macwelt.png
Encrypted	https://posteo.de/...creenshot_stampa.png
Encrypted	https://posteo.de/...shot_parisberlin.png
Encrypted	https://posteo.de/...r/screenshot_n24.png
Encrypted	https://posteo.de/...nshot_irishtimes.png
Encrypted	https://posteo.de/...reenshot_macwelt.png
Encrypted	https://posteo.de/images/ripe.png
Encrypted	https://posteo.de/images/tux.png
Encrypted	https://posteo.de/...s/logo_gpe-strom.png
Encrypted	https://posteo.de/...es/100pro_puzzle.png

Encryption of Outbound Links

Ideally, an encrypted page should only have links that lead to other encrypted pages. If plaintext links are used, passive network attackers can see where people go after they visit your web site. It's also possible that some sensitive information is leaked in the Referer header.

29 link(s)
29 out of 29 are encrypted View all

Status	Link
Encrypted	https://www.theguardian.com/...rman-way-patrik-lohr
Encrypted	https://www.planet-wissen.de/...sieihredaten100.html
Encrypted	https://www.test.de/...nicht-mit-4806144-0/
Encrypted	https://www.heise.de/...ANE-ein-2187144.html
Encrypted	https://www.deutschlandfunk.de/...ose-post.684.de.html
Encrypted	https://www.faz.net/...lungen-12280219.html
Encrypted	https://web.archive.org/...014/mum072014-17.pdf
Encrypted	https://www.heise.de/...Pinning-2849267.html
Encrypted	https://web.archive.org/...au/220816/index.html
Encrypted	https://www.heise.de/...al-Egal-2215573.html
Encrypted	https://www.heise.de/...ymitaet-3235713.html
Encrypted	https://www.heise.de/...hiv/2015/24/seite-76
Encrypted	https://www.heise.de/...nuegend-1934075.html
Encrypted	https://www.computerbild.de/...Posteo-10120025.html
Encrypted	https://www.tagesspiegel.de/...ichtig/11713676.html
Encrypted	https://www.linux-magazin.de/...uesselung-bei-Posteo
Encrypted	https://praxistipps.chip.de/...-im-ueberblick_23893
Encrypted	https://futurzwei.org/article/posteo
Encrypted	https://netzpolitik.org/...atsdatenspeicherung/
Encrypted	https://www.spiegel.de/...ensten-a-938948.html
Encrypted	https://www.sueddeutsche.de/...e-kunden-1.1749238-2
Encrypted	https://www.heise.de/...iv/2015/13/seite-138
Encrypted	https://www.irishtimes.com/...mous-email-1.2408853
Encrypted	https://www.berliner-zeitung.de/...hoher-schutz-li.6151
Encrypted	https://www.macwelt.de/...-anonym-8858696.html
Encrypted	https://web.archive.org/...0z99IwuK/pagina.html
Encrypted	https://web.archive.org/...anbieter-posteo.html
Encrypted	https://www.irishtimes.com/...mous-email-1.2408853
Encrypted	https://www.macwelt.de/...-anonym-8858696.html

HTTP Strict Transport Security

HTTP Strict Transport Security (HSTS) vastly improves security of the network encryption layer. With HSTS enabled, browsers no longer allow clicking through certificate warnings errors, which are typically trivial to exploit. Additionally, they will no longer submit insecure (plaintext) requests to the site in question, even if asked.

Test passed

Everything seems to be well configured. Well done.

HSTS Policy Main host

URL from which this policy was obtained.Location	https://www.posteo.de/
Specifies policy duration. Once activated, HSTS stays in force until this time lapses. Browsers update policy cache duration every time they receive a new HSTS header from a site.max‑age	31,536,000 seconds (about 1 year)
When present, this directive forces HSTS activation on allsubdomains. For best security, HSTS should be deployed on the bare domain name (e.g., example.com) and all its subdomains.includeSubDomains
Presence of this directive indicates that a web site wishes to permanently use HSTS and that its policy information should be preloaded (embedded in browsers).preload

Analysis

Policy is valid

OK. Your HSTS policy uses correct syntax.

Long policy age

Your HSTS policy has a long max-age value, which offers better protection.

Policy covers subdomains

When subdomains are included, network attackers are unable to manufacture arbitrary subdomains to manipulate cookies and trick users.

Redirection from HTTP to HTTPS to the same host

Good. The redirection from HTTP to HTTPS is to the same host. This approach ensures that HSTS is activated on the hostname when it's accessed via plaintext.

Policy preloaded

Excellent. This host is covered by a preloaded HSTS policy.

Preloaded host: posteo.de; includeSubDomains=true

HSTS Policy Apex host

URL from which this policy was obtained.Location	https://posteo.de/en
Specifies policy duration. Once activated, HSTS stays in force until this time lapses. Browsers update policy cache duration every time they receive a new HSTS header from a site.max‑age	31,536,000 seconds (about 1 year)
When present, this directive forces HSTS activation on allsubdomains. For best security, HSTS should be deployed on the bare domain name (e.g., example.com) and all its subdomains.includeSubDomains
Presence of this directive indicates that a web site wishes to permanently use HSTS and that its policy information should be preloaded (embedded in browsers).preload

Analysis

Policy is valid

OK. Your HSTS policy uses correct syntax.

Long policy age

Your HSTS policy has a long max-age value, which offers better protection.

Policy covers subdomains

When subdomains are included, network attackers are unable to manufacture arbitrary subdomains to manipulate cookies and trick users.

Preload intent declared

Good. With the preload directive set, browsers have a green light to embed the HSTS policy.

Redirection from HTTP to HTTPS to the same host

Good. The redirection from HTTP to HTTPS is to the same host. This approach ensures that HSTS is activated on the hostname when it's accessed via plaintext.

Policy preloaded

Excellent. This host is covered by a preloaded HSTS policy.

Preloaded host: posteo.de; includeSubDomains=true

HTTP Public Key Pinning

HTTP Public Key Pinning (HPKP) enables site operators to restrict which certificates are considered valid for their domain names. With a valid HPKP configuration, sites can defeat man in the middle (MITM) attacks using fraudulent or misissued certificates. HPKP is an advanced feature, suitable for use by only high-profile web sites.

Feature not applicable, not implemented, or disabled

Your server doesn't support this feature.

Content Security Policy

Content Security Policy (CSP) is a security mechanism that allows web sites control how browsers process their pages. In essence, sites can restrict what types of resources are loaded and from where. CSP policies can be used to defend against cross-site scripting, prevent mixed content issues, as well as report violations for investigation.

Test passed

Everything seems to be well configured. Well done.

content-security-policy

connect-src	https://api.posteo.de https://payment.posteo.de https://cdn.posteo.de wss://posteo.de 'self'
child-src	'self'
font-src	'self' data:
form-action	https://www.paypal.com https://hooks.stripe.com 'self' data:
frame-ancestors	'self'
frame-src	'self' blob:
img-src	data: *
manifest-src	'self'
media-src	'self' https://cdn.posteo.de
object-src	'self'
script-src	'self' This parameter shouldn't be used because it reenables insecure behavior that CSP disables by default.'unsafe-inline' This parameter shouldn't be used because it reenables insecure behavior that CSP disables by default.'unsafe-eval'
style-src	'self' This parameter shouldn't be used because it reenables insecure behavior that CSP disables by default.'unsafe-eval' This parameter shouldn't be used because it reenables insecure behavior that CSP disables by default.'unsafe-inline'
default-src	'none'
referrer	no-referrer

Analysis

Inline scripts are allowed

By default, CSP doesn't allow inline script execution, but this policy overrides that behavior by specifying 'unsafe-inline' in the 'script-src' directive. As a result, all XSS defenses provided by CSP are significantly weakened.

Inline styles are allowed

This policy allows inline styles. Although they are not as bad as inline scripts in terms of security, an injection bug in script area would allow the attacker to modify page appearance.

Dynamic code execution is allowed

By default, CSP doesn't allow dynamic script execution via eval and friends, but this policy overrides that behavior by specifyin 'unsafe-eval' in the 'script-src' directive. As a result, XSS defenses provided by CSP are significantly weakened.

Mixed content not blocked

This CSP policy doesn't use any of the directives designed to handle mixed content. Consider using the 'block-all-mixed-content' and 'upgrade-insecure-requests' directives as appropriate to ensure that no mixed content is allowed.

Analysis

CSP policy detected

Header: content-security-policy

Value: connect-src https://api.posteo.de https://payment.posteo.de https://cdn.posteo.de wss://posteo.de 'self'; child-src 'self'; font-src 'self' data:; form-action https://www.paypal.com https://hooks.stripe.com 'self' data:; frame-ancestors 'self'; frame-src 'self' blob:; img-src data: *; manifest-src 'self'; media-src 'self' https://cdn.posteo.de; object-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-eval' 'unsafe-inline'; default-src 'none'; reflected-xss block; referrer no-referrer;

Location: https://posteo.de/en

Subresource Integrity

Subresource Integrity (SRI) is a new standard that enables browsers to verify the integrity of embedded page resources (e.g., scripts and stylesheets) when they are loaded from third-party web sites. With SRI deployed, remote resources can be used safely, without fear of them being modified by malicious parties.

Test passed

Everything seems to be well configured. Well done.

13 script(s)
13 out of 13 are secure View all

Status	Link
Local	/javascripts/basics.js?v=d88da56a8780f029e5a1c69f923fee3dee6deccd34e1a1a7e483ed90915d1f33
Local	/javascripts/feedback-messages.js?v=5b3c7ed12c83c88d514941da51d1b0dca811b6a79fa37c04849a57fcdcfac7d6
Local	/javascripts/responsive-nav/responsive-nav.min.js?v=5d47eb204f81fe54346e3df06b20ae223985de67d9f50fdbc240a4860e3ee663
Local	/javascripts/responsive-nav/responsive-nav-init.js?v=92f76257e9b88e0b2f905a48eeb0fd07f9035291ea995fb2759e2e3dead8c8a8
Local	/javascripts/posteo-website-onscroll.js?v=4d0510db934acb6e5b089f9b84a4d6a209ca21bf81473a719494230e82adb737
Local	/javascripts/posteo-website.js?v=b6c8a5fad63b69eb54c0eeb8be6c328e78c5c38d98f913b10e2bd9d7f885a173
Local	/javascripts/swiper/swiper-bundle.min.js?v=b2e75dca9832b7cd63ea5c0c8062bdc359389fc23090e2fec375769503db798a
Local	/javascripts/swiper/swiper-init-stage-slider.js?v=d822d90bd539261746e6525eb172906cb7e2a523b7441bbbcd24820dd4418e55
Local	/javascripts/swiper/swiper-init-press-slider.js?v=902b2a8a82d407245237d4952cff78b8bfd6e6f66407db04accfe48096026f06
Local	/javascripts/p-wm_detectTouchOrMouse.js?v=bb797df1e71d57634cf984bf7a4323da229f5c8db7e051e30da36fffb83125ea
Local	/javascripts/ie11-polyfills.js?v=70cf6836f50e58d969e830d0ab395a1f66e1df1b233fee7e01b5c693bad4bbb2
Local	/javascripts/toggle-password-visibility.js?v=d123fc39c7d87fc8855e92f0f83cbe85030429c293150f3bf95a998d2af7a16b
Local	/javascripts/toggle-password-visibility-login.js?v=f5854b57c5f3e7fa9372c899ec9c06befee0ba32c4ef364762d083456f0b3476

4 CSS file(s)
4 out of 4 are secure View all

Status	Link
Local	/stylesheets/toggle-password-visibility.css?v=5903df83e4e4e1cb8eb419c17ca0c93463b10f0a040f03293c4b2e9ab9e1ae1a
Local	/stylesheets/swiper/swiper-bundle.min.css?v=d2b122cc89a676fdb573305db71c99480ea4553bc832916921ba7a3d80126966
Local	/stylesheets/p_styles-website.css?v=9f0cb05e1d56e151b0905158d677eb0b36bcc3c4ec7bc4e7906504ec7a68ee93
Local	/stylesheets/p_print_website.css?v=696354daf4a32e6fbd1553b278e26a208343d499d4f8d8ea70ed2f98bb4d9950

Analysis

No remote resources

The homepage of this site doesn't contain any remote resources so SRI is not needed.

Expect CT

Expect-CT is a deprecated response HTTP header designed to enable web sites to monitor problems related to their Certificate Transparency (CT) compliance. Should any CT issues arise, browsers that supported this header will submit reports to the specified reporting endpoint. Chrome was the browser that introduced support for this response header, but later deprecated it and removed it in version 107.

Test passed

Everything seems to be well configured. Well done.

Expect-CT Policy

URL from which this policy was obtained.Location	https://www.posteo.de/
Specifies policy duration. Once activated, Expect-CT stays in force until this time lapses. Browsers update policy cache duration every time they receive a new Expect-CT header from a site.max‑age	300 seconds (about 5 minutes)
This optional directive controls whether CT compliance will be enforced by your policy. It's useful if you're confident in your configuration and wish to deploy CT before browsers start enforcing it.enforce
This optional directive enables reporting and specifies the endpoint clients should use to submit reports.report-uri

Analysis

Deploy Expect-CT reporting

This policy doesn't use reporting, which means that you will not found out about any problems with CT compliance. We recommend adding the reporting for better situational awareness.

Analysis

Header information

Policy text: enforce, max-age=300

Expect-CT enabled

Excellent. This web site has a valid Expect-CT policy.

Frame Options

The X-Frame-Options header controls page framing, which occurs when a page is incorporated into some other page, possibly on a different site. If framing is allowed, attackers can employ clever tricks to make victims perform arbitrary actions on your site; they do this by showing their web site while forwarding the victim's clicks to yours.

Test passed

Everything seems to be well configured. Well done.

Analysis

Header information

Name: x-frame-options

Value: SAMEORIGIN

Framing allowed from the same origin only

OK. Your site allows page framing only from itself. This should generally be safe, except maybe on sites that host user content.

XSS Protection

Some browsers ship with so-called XSS Auditors, built-in defenses against XSS. Although these defenses work against simple reflective XSS attacks, they can be abused by skillful attackers to add weaknesses to otherwise secure web sites. These dangers are present in both filtering and blocking modes. At this time, the Safari browser ships with its XSS defenses enabled by default. For this reason, the best approach is to explicitly disable this functionality.

Feature not applicable, not implemented, or disabled

Your server doesn't support this feature.

Analysis

Explicitly disable browser XSS protection

For best security, every web site should explicitly disable browser-based XSS protection. This is because this type of functionality can be used to introduce vulnerabilities into otherwise error-free web sites.

Content Type Options

Some browsers use a technique called content sniffing to override response MIME types provided by HTTP servers and interpret responses as something else (usually HTML). This behavior, which could potentially lead to security issues, should be disabled by attaching an X-Content-Type-Options header to all responses.

Test passed

Everything seems to be well configured. Well done.

Analysis

Header information

Name: x-content-type-options

Value: nosniff

Valid configuration

Good. Your configuration is valid. This means that browsers won't try to guess file MIME type on this web site.

Public Report | posteo.de

posteo.de

Domain Name System

Email

WWW

DNS Zone

Nameserver Names

Nameserver Addresses

Start of Authority (SOA) Record

Analysis

Backing DNS Queries

DNS Records

DNS Records

Backing DNS Queries

DNSSEC

Analysis

Useful DNSSEC Tools

Certification Authority Authorization

CAA Policy Information

Analysis

Email (SMTP)

Analysis

Email TLS (SMTP)

TLS Configuration: mx04.posteo.de (185.67.36.64) Cached

Analysis

TLS Configuration: mx04.posteo.de (185.67.36.71) Cached

Analysis

TLS Configuration: mx01.posteo.de (185.67.36.61) Cached

Analysis

TLS Configuration: mx01.posteo.de (185.67.36.62) Cached

Analysis

TLS Configuration: mx03.posteo.de (185.67.36.70) Cached

Analysis

TLS Configuration: mx03.posteo.de (185.67.36.63) Cached

Analysis

Email Certificates (SMTP)

Certificate #1 Cached

Analysis

Certificate Chain

Analysis

Email DANE (SMTP)

DANE: mx04.posteo.de (185.67.36.64)

Analysis

DANE: mx04.posteo.de (185.67.36.71)

Analysis

DANE: mx01.posteo.de (185.67.36.61)

Analysis

DANE: mx01.posteo.de (185.67.36.62)

Analysis

DANE: mx03.posteo.de (185.67.36.70)

Analysis

DANE: mx03.posteo.de (185.67.36.63)

Analysis

SPF

SPF Policy Information Main policy

Analysis

DMARC

DMARC Policy Information

Analysis

MTA Strict Transport Security

MTA-STS Policy Indicator

Analysis

MTA-STS Policy

Analysis

Certificate: mta-sts.posteo.de

Analysis

Certificate Chain

Analysis

SMTP TLS Reporting

TLS-RPT Policy

Analysis

HTTP (80)

URL: http://posteo.de/

Analysis

URL: http://www.posteo.de/

Analysis

HTTP (443)

URL: https://posteo.de/

URL: https://www.posteo.de/

WWW TLS