Reverse DNS (PTR): why it matters and how to fix it

A server without a valid PTR starts at a disadvantage. What it is, how to check it and make it forward-confirmed.

What the PTR record is

Reverse DNS (PTR) maps an IP address to a hostname. When your server connects to deliver an email, the receiver checks the IP's PTR: if it's missing or inconsistent, the message starts under suspicion.

Forward-confirmed (FCrDNS)

Having a PTR isn't enough: the returned name must resolve back to the same IP. Example: 1.2.3.4 → mx.yourdomain.com and mx.yourdomain.com → 1.2.3.4. This consistency is called forward-confirmed reverse DNS.

How to fix it

• Set the PTR from your IP/hosting provider's panel (usually not your own DNS).
• Create the matching A/AAAA record on your domain.
• Use the same hostname in your SMTP server's HELO/EHLO.