Create a Free SMTP Monitor
  • Don't get surprised by email server performance issues
  • Get instant reports on mail server performance, open relay status, and more
Create Monitor

SMTP Reverse DNS Mismatch

What you see when your domain has this problem
Reverse DNS does not contain the hostname Details area Ignore

More Information About Smtp Reverse Dns Mismatch

The forward lookup (A) of the hostname hostname did not match the reverse lookup (PTR) for the IP Address. 

Example of a correctly matching pair of records:

(A) lookup for resolves to

(PTR) lookup for reverses to

Additional Information

Some receiving mail servers may use this as an indication of a possible spam source in a scoring system.  Most will not reject incoming mail solely on this basis.  We recommend that you contact your ISP and ask them to setup a reverse record (PTR) that matches the hostname of your mail server.