[Flibnipktz]

Thanks for the link to mxtoolbox. A mailserver test of our IP did in fact error:

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 smtp.mxtoolbox.com resolves to 208.123.79.38

(PTR) lookup for 208.123.79.38 reverses to smtp.mxtoolbox.com

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.

Could this really be why we've been blacklisted by att.net for a week as of today? I would think the ISP would have stumbled upon this by now. Anyway, forwarding to them.

--------------- Added [DATE]1443972040[/DATE] at [TIME]1443972040[/TIME] ---------------

Originally Posted by Dave

It depends.
If you have an unmanaged server then the host is not responsible for anything that's installed or misconfigured on your server. If it's a managed server however, they have a lot more responsibility.

I believe it's managed but would have to double check.