DNS record types · Updated

DNS PTR record

A PTR (pointer) record maps an IP address back to a hostname. It is the record behind a reverse DNS lookup, and it is held in a special reverse zone rather than in your own domain.

Look up a PTR record

Check what DNS returns right now:

Format and example

10.113.0.203.in-addr.arpa.   3600   IN   PTR   mail.example.com.
  • Name: The address with its parts reversed, under in-addr.arpa for IPv4 or ip6.arpa for IPv6.
  • TTL: Seconds a resolver may cache the answer.
  • Hostname: The name for the address. For a mail server it should be the name the server announces and should resolve back to the same address.

Common mistakes

  • Trying to add the record in your own domain's zone. It lives in the zone of whoever owns the IP address block, so you set it through your hosting or internet provider.
  • A PTR name that does not resolve back to the same address. Mail servers treat that as suspicious.
  • Leaving the provider's generated name (built from the address) on a mail server.
  • Publishing several PTR records for one address. Some software reads only the first.

Related record types

A record, AAAA record. The DNS record types guide compares them all.

Frequently asked questions

What is a PTR record?

A pointer record that maps an IP address to a hostname, the reverse of an A or AAAA record. It answers the question "which name belongs to this address?"

Who sets a PTR record?

The owner of the IP address block: your hosting provider for a server, your internet provider for a line. It is configured in their control panel or by request.

Why do mail servers need a PTR record?

Receiving servers check that a sending address has a PTR record whose name resolves back to it. Without one, mail is more likely to be rejected or filtered.

How do I look up a PTR record?

Use the lookup above, or run dig -x 8.8.8.8 +short, or nslookup 8.8.8.8.