DNS Record Types Explained

DNS records are typed answers about a name. The type tells you what the value means: an address, a mail route, a delegation, or another instruction. Looking at the right type prevents a common diagnostic error, such as assuming that working web DNS proves email is configured.

Address and alias records

A maps a name to an IPv4 address; AAAA maps it to an IPv6 address. A hostname can have more than one address, and clients may choose among them. CNAME makes one name an alias of another name, so its target must also resolve. An address is not a promise that the application at that address is healthy.

For example, www.example.com could point to a hosting provider while mail for example.com is handled elsewhere. These are separate DNS questions.

Mail, delegation, and text

MX identifies the mail exchangers for a domain and includes preference values. NS lists nameservers involved in delegation and zone authority. TXT stores text; verification tokens and policies such as SPF-related data use it, but its meaning depends on the application reading it. A TXT answer alone does not prove a complete mail security setup.

CAA expresses which certificate authorities may issue certificates for a domain. It is distinct from an HTTPS certificate already installed on a server. DNSSEC uses additional record types and signatures to authenticate DNS data; it does not encrypt ordinary web traffic.

Read records in context

At /whois, inspect the exact hostname and compare related records. If www resolves but the bare domain does not, check each name separately. If email fails, start with MX and the mail host rather than A for the website. When a record recently changed, old answers can remain in caches for their TTL.

The DNS check guide provides a practical sequence. Do not treat an empty record set or NXDOMAIN as proof of registration availability.

Sources

• RFC 1035: DNS resource records
• RFC 3596: AAAA records for IPv6
• RFC 8659: CAA records