Reverse DNS / PTR Setup Guide

Problem

Mail diagnostics show that the sending IP has no reverse DNS (PTR) or the value is wrong.

Symptoms

• Email Deliverability reports missing rDNS.
• Some receivers reduce trust or delivery quality for the sending IP.
• Reverse lookups return no answer or a generic provider hostname.

Top 3 Causes

1. PTR was never configured by the IP owner - The provider-side reverse zone has no record.
2. PTR does not align with the sending hostname - The advertised mail hostname and reverse DNS do not match operationally.
3. The IP changed but PTR was not updated - Server or network changes left the old reverse DNS value behind.

Diagnose with DechoNet

• Email Deliverability Test to confirm the sending IP and whether rDNS is missing.
• IP Check to verify the active public IP used for outbound mail.

Resolution Checklist

• Confirm the exact public IP used for outbound mail.
• Find where your cloud or hosting provider manages PTR for that IP.
• Set the PTR value to the hostname you actually use for mail sending.
• If needed, make sure the forward A record also points back consistently.
• Re-run Email Deliverability Test and confirm rDNS is now detected.

When to Escalate

• Escalate to the provider if you do not control reverse DNS for the IP range directly.
• If you manage multiple sending IPs, align hostname conventions with the mail platform owner first.