DE EN IT

~/glossary / DNS

PTR record

A PTR record provides reverse DNS: it maps an IP address back to a hostname.

daniele@mikweb: ~/glossary — man ptr-record

PTR records live in special zones such as in-addr.arpa (IPv4) and ip6.arpa (IPv6). Those zones belong to whoever owns the IP block, usually the hosting provider, not the domain owner. You set the PTR in the provider's control panel or via a ticket.

For mail servers a PTR is mandatory in practice: many receivers reject or penalise connections from IPs without one. The clean setup is forward-confirmed reverse DNS (FCrDNS): the PTR points to mail.example.com, and that name resolves back to the same IP.

Common issue: the PTR still shows the provider's generic name (e.g. static-203-0-113-10.provider.net). A HELO name that does not match the PTR also hurts deliverability.

Example

dig +short -x 203.0.113.10
daniele@mikweb: ~/glossary — ls

Related terms

MX recordAn MX record lists the mail servers that accept email for a domain, each with a priority.SPFSPF (Sender Policy Framework) is a TXT record that defines which servers are allowed to send email on behalf of a domain.A and AAAA recordAn A record maps a hostname to an IPv4 address; an AAAA record maps it to an IPv6 address.SMTPSMTP (Simple Mail Transfer Protocol) is the protocol used to transfer email between mail servers and from mail clients to their server.

← All terms