DNS CNAME and A/AAAA Records

We share the most important informationabotu DNS Records and how to use them for different purposes like mail txt and subdomains.

Janis König

Last Update

16.12.2025

The Domain Name System (DNS) uses different types of records for name resolution, including MX (mail), TXT (various). The A and AAAA records are used to match a domain to an IPv4 and IPv6 address, respectively:

Type	Entry	Pointer
A	example.org	192.0.2.42
AAAA	example.org	2001:db8:1234::42
A	vpn.example.org	192.0.2.137

In this case, the domain example.org will be resolved to a different IP than vpn.example.org , and the latter only being reachable through IPv4.

In addition, there exist CNAME records which allow to point a domain to another domain, triggering a an A/AAAA record lookup only through indirection:

Type	Entry	Pointer
CNAME	www.example.org	example.org

Here, the www-subdomain www.example.org should point to whatever the second level domain should point to.

DNS CNAME and A/AAAA Records

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