What is a PTR record? Reverse DNS for mail servers

Q: Who controls your PTR record?

Here’s the catch that trips people up: you don’t set your PTR record in your own DNS. It’s controlled by whoever owns the IP block — your hosting provider or ISP. You set the forward A record yourself, but you request the matching PTR from your provider (see our guide on configuring a PTR in your hosting panel).

Quick answer

A PTR record (pointer record) is the piece of DNS that maps an IP address back to a hostname — the reverse of the usual name-to-IP lookup. It’s small, easily overlooked, and absolutely critical if you send email from your own server.

Forward DNS vs reverse DNS

Normal (forward) DNS answers “what IP is example.com?” using an A record. Reverse DNS answers the opposite: “what hostname belongs to this IP?” using a PTR record. So mail.example.com resolves to an IP via its A record, and that IP resolves back to mail.example.com via its PTR record. When both agree, the pair is trustworthy.

Why do mail servers require reverse DNS?

Receiving mail servers treat a missing or generic PTR record as a strong spam signal. Legitimate mail servers have a proper PTR; spam from compromised machines and home connections usually doesn’t. Many servers will reject or heavily penalise mail from an IP whose PTR is missing, or that points to a generic ISP-assigned name like host-203-0-113-45.isp.net.

Who controls your PTR record?

Here’s the catch that trips people up: you don’t set your PTR record in your own DNS. It’s controlled by whoever owns the IP block — your hosting provider or ISP. You set the forward A record yourself, but you request the matching PTR from your provider (see our guide on configuring a PTR in your hosting panel).

Checking your PTR record

Use our Reverse DNS tool to see the PTR (hostname) registered for any IPv4 address. If it returns nothing, the IP has no PTR — a problem for a mail server. If it returns a generic ISP name rather than your mail hostname, that’s also worth fixing for deliverability.

The gold standard: FCrDNS

The strongest setup is Forward-Confirmed Reverse DNS, where the PTR points to a hostname whose A record points back to the same IP — a matching round trip. Many strict mail systems require it. See our guide on fixing FCrDNS errors.