PTR Record (Reverse DNS)
A PTR record maps a sending IP back to a hostname. Receivers check it early in the SMTP handshake, and a missing PTR is a trust penalty.
Product & Engineering · July 17, 2026 · 1 min read
A PTR record, or reverse DNS, maps a sending IP address back to a hostname, the reverse of a normal DNS lookup. Receiving servers check it at the very start of the SMTP handshake.
A missing or mismatched PTR is an early trust penalty applied before your content is ever read. On shared infrastructure it is set for you; on a dedicated setup it must be configured deliberately.
See the full guide: Related: DNS records for email.
Resources in this guide
| Property | Value |
|---|---|
| Type | Reverse DNS |
| Maps | IP to hostname |
| Checked | Start of SMTP handshake |
Frequently asked questions
Why does a PTR record matter?
Receivers check reverse DNS at the start of the connection. A missing or mismatched PTR signals an untrustworthy sender before your message content is even evaluated.
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