Look up any record type
Pick a type and see what resolvers around the world return:
The common types at a glance
| Type | Points to | Typical use | Example value |
|---|---|---|---|
| A | An IPv4 address | The address of a website or server | 203.0.113.10 |
| AAAA | An IPv6 address | The same, over IPv6 | 2001:db8::10 |
| CNAME | Another name | Make www or a subdomain an alias of a host | cdn.example.net |
| MX | A mail server name, with a priority | Where email for the domain is delivered | 10 mail.example.com |
| TXT | Free text | SPF, DKIM, DMARC and site verification | v=spf1 -all |
| NS | A nameserver name | Which servers hold the domain's records | ns1.example.net |
| SOA | Zone details | Primary server, contact, serial number and timers | ns1.example.net hostmaster.example.com 2026110801 … |
| PTR | A hostname, for an IP address | Reverse lookups, mostly for mail servers | mail.example.com |
| SRV | Host, port, priority and weight | Find the server for a service such as SIP or XMPP | 10 5 5060 sip.example.com |
| CAA | A certificate authority | Limit who may issue TLS certificates for the domain | 0 issue "letsencrypt.org" |
Rules that cause the most trouble
- A CNAME can't share a name with another record. That includes the root of a domain, which always has SOA and NS records. Use an A record there, or your DNS host's ALIAS/ANAME feature if it has one.
- MX and NS must point to names, not addresses, and the name must have an A or AAAA record of its own. An MX that points to a CNAME is invalid.
- A domain should have exactly one SPF record. SPF lives in a TXT record, and two of them make SPF fail. See SPF record syntax.
- More than one A record is fine. Resolvers return them all, and clients pick one, which spreads traffic crudely.
Which record for which job
- Put a website on a server: an A record (and AAAA if the server has IPv6).
- Point a subdomain at a hosting or CDN service: a CNAME to the name the service gives you.
- Receive email: MX records. Prove your mail is genuine: TXT records for SPF, DKIM and DMARC.
- Move DNS to another provider: change the NS records at your registrar.
- Make your mail server look legitimate: a PTR record on its IP address, set by whoever owns the address. See reverse DNS lookup.
Every record also has a TTL, and a change takes as long as the old TTL to reach everyone, as explained in how long DNS propagation takes.