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.

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 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.

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.

Backing DNS Queries

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

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.

DNS Records

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

Backing DNS Queries

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

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.

Useful DNSSEC Tools

• Test cornubot.se @ DNSViz
• Test cornubot.se @ DNSSEC Analyzer (Verisign Labs)
• Zonemaster (iiS and AFNIC)

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.

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.

220 mx.google.com ESMTP d75a77b69052e-4a994af414csi142454341cf.515 - gsmtp

EHLO outbound.hardenize.com
250-mx.google.com at your service, [172.99.67.55]
250-SIZE 157286400
250-8BITMIME
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-CHUNKING
250 SMTPUTF8

STARTTLS
220 2.0.0 Ready to start TLS

220 mx.google.com ESMTP 5b1f17b1804b1-454d505e3dfsi16795095e9.163 - gsmtp

EHLO outbound.hardenize.com
250-mx.google.com at your service, [172.99.67.55]
250-SIZE 157286400
250-8BITMIME
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-CHUNKING
250 SMTPUTF8

STARTTLS
220 2.0.0 Ready to start TLS

220 mx.google.com ESMTP 5b1f17b1804b1-454d50c7546si16759435e9.97 - gsmtp

EHLO outbound.hardenize.com
250-mx.google.com at your service, [172.99.67.55]
250-SIZE 157286400
250-8BITMIME
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-CHUNKING
250 SMTPUTF8

STARTTLS
220 2.0.0 Ready to start TLS

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.

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.

Certificate #1

Leaf certificate mx.google.com
Issuer: Google Trust Services LLC
Not Before: 17 Jun 2025 20:02:56 UTC
Not After: 09 Sep 2025 20:02:55 UTC (expires in 2 months 55 minutes)
Key: EC 256 bits
Signature: SHA256withRSA
 View details

Names	mx.google.com smtp.google.com aspmx.l.google.com alt1.aspmx.l.google.com alt2.aspmx.l.google.com alt3.aspmx.l.google.com alt4.aspmx.l.google.com gmail-smtp-in.l.google.com alt1.gmail-smtp-in.l.google.com alt2.gmail-smtp-in.l.google.com alt3.gmail-smtp-in.l.google.com alt4.gmail-smtp-in.l.google.com gmr-smtp-in.l.google.com alt1.gmr-smtp-in.l.google.com alt2.gmr-smtp-in.l.google.com alt3.gmr-smtp-in.l.google.com alt4.gmr-smtp-in.l.google.com mx1.smtp.goog mx2.smtp.goog mx3.smtp.goog mx4.smtp.goog aspmx2.googlemail.com aspmx3.googlemail.com aspmx4.googlemail.com aspmx5.googlemail.com gmr-mx.google.com
Subject DN	CN=mx.google.com
Subject Key Identifier	27d95b107189a4ad313012b47a7f5afbcc2fac54
Serial	38f33de7f191160d103339bab5954191
Not Before	17 Jun 2025 20:02:56 UTC
Not After	09 Sep 2025 20:02:55 UTC
Validity period	84 days
Key Usage	digitalSignature
Extended Key Usage	serverAuth
Must Staple	No
Issuer
Issuer DN	CN=WR2, O=Google Trust Services, C=US
Certification Authority	Google Trust Services LLC
Validation Type	Domain Validation (DV)
Authority Key Identifier	keyid:de1b1eed7915d43e3724c321bbec34396d42b230
Parent Certificate	http://i.pki.goog/wr2.crt
CRL	http://c.pki.goog/wr2/oBFYYahzgVI.crl
OCSP	http://o.pki.goog/wr2
Certificate Transparency
Signed Certificate Timestamps	17 Jun 2025 21:02:59 UTC | Google 'Xenon2025h2' log | Qualified 17 Jun 2025 21:02:59 UTC | Cloudflare 'Nimbus2025' | Qualified
Fingerprints
SHA1	634044e4ab6f5026962d918b99e85e0f59a72e7f
SHA256	3e018924f14664fa3eabe3c4bde8ea8d5a50b98e085d7369c93ec513cec1b54d
SPKI SHA256	ff2c6d6f4fb181fa6e6c28d5435e96b7738768ef1a3eec6b3a34772567923682

Analysis

Good

Strong private key

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

Good

Strong signature algorithm

Good. This certificate uses a strong signature algorithm.

Good

Certificate matches hostname

Good. The provided certificate matches the expected hostnames.

Good

Certificate dates match

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

Good

Certificate has not been revoked

Good. This certificate has not been revoked.

Good

Certificate satisfies Apple's CT compliance requirements

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

Certificate Chain

Leaf certificate

mx.google.com | 3e01892
Not After: 09 Sep 2025 20:02:55 UTC (expires in 2 months 55 minutes)
Authentication: EC 256 bits (SHA256withRSA)
 View details

Names	mx.google.com smtp.google.com aspmx.l.google.com alt1.aspmx.l.google.com alt2.aspmx.l.google.com alt3.aspmx.l.google.com alt4.aspmx.l.google.com gmail-smtp-in.l.google.com alt1.gmail-smtp-in.l.google.com alt2.gmail-smtp-in.l.google.com alt3.gmail-smtp-in.l.google.com alt4.gmail-smtp-in.l.google.com gmr-smtp-in.l.google.com alt1.gmr-smtp-in.l.google.com alt2.gmr-smtp-in.l.google.com alt3.gmr-smtp-in.l.google.com alt4.gmr-smtp-in.l.google.com mx1.smtp.goog mx2.smtp.goog mx3.smtp.goog mx4.smtp.goog aspmx2.googlemail.com aspmx3.googlemail.com aspmx4.googlemail.com aspmx5.googlemail.com gmr-mx.google.com
Subject DN	CN=mx.google.com
Subject Key Identifier	27d95b107189a4ad313012b47a7f5afbcc2fac54
Serial	38f33de7f191160d103339bab5954191
Not Before	17 Jun 2025 20:02:56 UTC
Not After	09 Sep 2025 20:02:55 UTC
Validity period	84 days
Key Usage	digitalSignature
Extended Key Usage	serverAuth
Must Staple	No
Issuer
Issuer DN	CN=WR2, O=Google Trust Services, C=US
Certification Authority	Google Trust Services LLC
Validation Type	Domain Validation (DV)
Authority Key Identifier	keyid:de1b1eed7915d43e3724c321bbec34396d42b230
Parent Certificate	http://i.pki.goog/wr2.crt
CRL	http://c.pki.goog/wr2/oBFYYahzgVI.crl
OCSP	http://o.pki.goog/wr2
Certificate Transparency
Signed Certificate Timestamps	17 Jun 2025 21:02:59 UTC | Google 'Xenon2025h2' log | Qualified 17 Jun 2025 21:02:59 UTC | Cloudflare 'Nimbus2025' | Qualified
Fingerprints
SHA1	634044e4ab6f5026962d918b99e85e0f59a72e7f
SHA256	3e018924f14664fa3eabe3c4bde8ea8d5a50b98e085d7369c93ec513cec1b54d
SPKI SHA256	ff2c6d6f4fb181fa6e6c28d5435e96b7738768ef1a3eec6b3a34772567923682

Intermediate certificate

WR2 | e6fe22b
Not After: 20 Feb 2029 14:00:00 UTC (expires in 3 years 7 months)
Authentication: RSA 2048 bits (SHA256withRSA)
 View details

Subject DN	CN=WR2, O=Google Trust Services, C=US
Subject Key Identifier	de1b1eed7915d43e3724c321bbec34396d42b230
Serial	7ff005a07c4cded100ad9d66a5107b98
Not Before	13 Dec 2023 09:00:00 UTC
Not After	20 Feb 2029 14:00:00 UTC
Validity period	1897 days
Key Usage	digitalSignature, keyCertSign, cRLSign
Extended Key Usage	serverAuth, clientAuth
Issuer
Issuer DN	CN=GTS Root R1, O=Google Trust Services LLC, C=US
Certification Authority	Google Trust Services LLC
Validation Type	Not Applicable
Authority Key Identifier	keyid:e4af2b26711a2b4827852f52662ceff08913713e
Parent Certificate	http://i.pki.goog/r1.crt
CRL	http://c.pki.goog/r/r1.crl
CA certificate	Yes (pathlen 0)
Fingerprints
SHA1	66e4161260b100fee0de287a9a5293b4c2224ae6
SHA256	e6fe22bf45e4f0d3b85c59e02c0f495418e1eb8d3210f788d48cd5e1cb547cd4
SPKI SHA256	60fb4769fb4bc3aff4be773606734a185e78c62080dbc58571c723900e32a423

Intermediate certificate

GTS Root R1 | 3ee0278
Not After: 28 Jan 2028 00:00:42 UTC (expires in 2 years 6 months)
Authentication: RSA 4096 bits (SHA256withRSA)
 View details

Subject DN	CN=GTS Root R1, O=Google Trust Services LLC, C=US
Subject Key Identifier	e4af2b26711a2b4827852f52662ceff08913713e
Serial	77bd0d6cdb36f91aea210fc4f058d30d
Not Before	19 Jun 2020 00:00:42 UTC
Not After	28 Jan 2028 00:00:42 UTC
Key Usage	digitalSignature, keyCertSign, cRLSign
Issuer
Issuer DN	CN=GlobalSign Root CA, OU=Root CA, O=GlobalSign nv-sa, C=BE
Certification Authority	Google Trust Services LLC
Validation Type	Not Applicable
Authority Key Identifier	keyid:607b661a450d97ca89502f7d04cd34a8fffcfd4b
Parent Certificate	http://pki.goog/gsr1/gsr1.crt
CRL	http://crl.pki.goog/gsr1/gsr1.crl
OCSP	http://ocsp.pki.goog/gsr1
CA certificate	Yes (pathlen unlimited)
Fingerprints
SHA1	08745487e891c19e3078c1f2a07e452950ef36f6
SHA256	3ee0278df71fa3c125c4cd487f01d774694e6fc57e0cd94c24efd769133918e5
SPKI SHA256	871a9194f4eed5b312ff40c84c1d524aed2f778bbff25f138cf81f680a7adc67

Root certificate

GlobalSign Root CA | ebd4104
Not After: 28 Jan 2028 12:00:00 UTC (expires in 2 years 6 months)
Authentication: RSA 2048 bits (SHA1withRSA)
 View details

Subject DN	CN=GlobalSign Root CA, OU=Root CA, O=GlobalSign nv-sa, C=BE
Subject Key Identifier	607b661a450d97ca89502f7d04cd34a8fffcfd4b
Serial	040000000001154b5ac394
Not Before	01 Sep 1998 12:00:00 UTC
Not After	28 Jan 2028 12:00:00 UTC
Key Usage	keyCertSign, cRLSign
Issuer
Issuer DN	CN=GlobalSign Root CA, OU=Root CA, O=GlobalSign nv-sa, C=BE
Certification Authority	Google Trust Services LLC
Validation Type	Self-signed
CA certificate	Yes (pathlen unlimited)
Fingerprints
SHA1	b1bc968bd4f49d622aa89a81f2150152a41d829c
SHA256	ebd41040e4bb3ec742c9e381d31ef2a41a48b6685c96e7cef3c1df6cd4331c99
SPKI SHA256	2bcee858158cf5465fc9d76f0dfa312fef25a4dca8501da9b46b67d1fbfa1b64

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.

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.

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.

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.

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.

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.

URL: http://cornubot.se/

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.

URL: https://cornubot.se/

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.