DNS tool

Reverse DNS checker

Enter a mail server's IP address. You see its reverse name and whether that name resolves back to the same address, like the example.

Example resultReverse DNS · 3.33.152.147

The name does not point back

A reverse name is published, but it does not resolve back to this address — so it confirms nothing. Anyone controlling an address can publish any name they like.

3.33.152.147a4ec4c6ea1c92e2e6.awsglobalaccelerator.comresolves to 15.197.142.173, not 3.33.152.147

Addresses the name resolves to · 1

15.197.142.173

The check is whether this list contains the address you entered. That is the whole test: both directions have to agree.

Fixing this is not a change to your own domain's DNS. The reverse zone belongs to whoever controls the address — your hosting provider, your ISP, or your sending platform — so the fix is a request to them. If you send through a shared platform, the address is usually theirs to name and already set up.

Example result

Receiving mail servers read the reverse name of the address your mail arrives from — and a name on its own means nothing, because whoever controls the address publishes whatever name they like. So the real test is the round trip: does that name resolve back to the same address? This runs both lookups and shows you the addresses it compared, so a failure tells you which half is missing.

Diagnose your domain

Check SPF, DMARC, DKIM, MX, DNS health, blacklists and domain & SSL expiry in one free scan — with the exact record to paste in to fix each problem.