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 astermail.org @ DNSViz
• Test astermail.org @ 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.astermail.org ESMTP ready
EHLO outbound.hardenize.com
250-mx.astermail.org you had me at EHLO
250-STARTTLS
250-SMTPUTF8
250-SIZE 52428800
250-REQUIRETLS
250-PIPELINING
250-ENHANCEDSTATUSCODES
250-DSN
250-CHUNKING
250-BINARYMIME
250 8BITMIME
QUIT
221 2.0.0 Bye.

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.

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://astermail.org/

URL: http://www.astermail.org/

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://astermail.org/

URL: https://www.astermail.org/

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.