Glossary

PTR Record — Reverse DNS for Email Delivery

PTR is reverse DNS: IP → hostname. Big inboxes expect your sending IP to have a hostname that round-trips back to the same IP. Skip it and you’ll see 421s, spam folders, or silent drops.

Why PTR Records Matter for Email

Gmail and friends look up your IP’s name on connect. No PTR? You look like a random VPS blasting spam.

Forward-Confirmed Reverse DNS (FCrDNS)

They want the loop to close:

1. IP 192.0.2.1 → PTR → mail.example.com
2. mail.example.com → A → 192.0.2.1

If step two points somewhere else, you’re still suspect.

How to Add a PTR Record

You don’t set PTR next to your MX — your ISP or cloud panel sets rDNS for the IP. Open a ticket or use their “reverse DNS” UI.