DNS record types explained
A practical map of the DNS records used by websites, mail and domain security.
Definition and scope
A practical map of the DNS records used by websites, mail and domain security.
Use this reference to establish the meaning and limits of the result before changing production configuration.
How it works
DNS is a distributed database. A and AAAA map names to addresses; CNAME aliases one name; NS and SOA describe zone authority; MX routes mail; TXT carries policies; CAA limits certificate issuers; SRV publishes service endpoints; DS and DNSKEY form the DNSSEC chain.
How to read it
Read the owner name, type, TTL and value together. A short TTL allows faster changes but causes more resolver traffic. An authoritative answer and the AD flag are different facts: AD means a validating recursive resolver accepted the DNSSEC proof.
Correct and incorrect examples
Compare the normalized examples. Technical values are illustrative and use documentation ranges or reserved names.
example.com. 3600 IN A 192.0.2.10example.com. CNAME target.example.net. + A 192.0.2.10| Element | Role | Example |
|---|---|---|
| A | IPv4 | 192.0.2.10 |
| AAAA | IPv6 | 2001:db8::10 |
| CNAME | CNAME | www.example.com → edge.example.net |
| MX | MX preference | 10 mail.example.com |
| NS / SOA | NS / SOA | ns1.example.net |
| TXT | TXT | v=spf1 … |
| CAA | CA | 0 issue letsencrypt.org |
| SRV | Service | 10 5 443 host.example |
| DS / DNSKEY | DNSSEC | key-tag + digest |
| HTTPS / SVCB / TLSA | Modern service / DANE | priority + parameters |
Common problems
Typical faults are conflicting CNAME data, stale glue, missing trailing names, duplicate policy records and an incomplete DNSSEC chain. An empty record set is not automatically NXDOMAIN: the name may exist without that type.
Practical checklist
Check the exact hostname, compare both address families, inspect delegation from parent to child, and repeat only after the relevant TTL has expired. Preserve raw values when escalating to a DNS provider.
Standards and primary references
These primary specifications define the protocol behavior. Provider documentation may add operational requirements but cannot replace the standard.