Reverse DNS: maps an IP address back to a name.
PTR records live in the reverse zones in-addr.arpa (IPv4) and ip6.arpa (IPv6) and map an address back to a host name. They are set by whoever controls the address block, usually your hosting or cloud provider, not at your domain’s DNS host.
- Type
- PTR
- Code
- 12
- Defined in
- RFC 1035
- IANA description
- a domain name pointer
- Field: Name
- Host name for the address
How it works
Mail receivers check that a sending IP has a PTR whose name resolves back to the same IP (“forward-confirmed reverse DNS”). Google lists valid forward and reverse DNS for sending IPs as a requirement for all senders.
Example
10.2.0.192.in-addr.arpa. 3600 IN PTR mail.example.com.
Example uses reserved documentation names and addresses (RFC 2606, RFC 5737, RFC 3849).
Common mistakes
- Trying to add PTR records at your domain registrar (ask the IP’s provider).
- A PTR name that doesn’t resolve back to the same address.
How to check yours
To find out who controls reverse DNS for an address, look the address up: the network that owns it, usually your hosting or cloud provider, sets the PTR. Most cloud providers let you set it in the server or IP settings; for a home or office connection, the ISP usually has to do it.
For email
Required by Gmail for sending IPs; generic ISP-style PTR names often hurt reputation.
Related record types
Sources
Sources
- IANA: Resource Record (RR) TYPEs registry · checked 5 Oct 2026
- RFC 1035 · checked 5 Oct 2026