A PTR record maps a sending IP address back to a hostname. Mailbox providers check that the PTR resolves and that the hostname's A record points back to the same IP (forward-confirmed reverse DNS).
What good looks like#
- Done: Ask your hosting or ESP provider to set a PTR for each sending IP.
- Done: Use a hostname under your domain (mail1.example.com) rather than the provider's generic name.
- Done: Create the matching A record so forward and reverse agree.
- Done: Use the same hostname in the SMTP HELO/EHLO banner.
What bad looks like#
- Seen in audits: Generic PTRs like 203-0-113-10.provider.net.
- Seen in audits: HELO names that do not match the PTR.
How to move from bad to good#
Work through the good list in order and re-verify after each change. Most teams find one or two items from the bad list already present; fixing those usually produces the largest improvement.
Frequently asked questions#
Can I set PTR records in my own DNS?
No. PTRs live in the IP owner's reverse zone. Your hosting provider or ESP sets them, though some offer self-service.