Okay, I ran a test on my DNS at dnsreport.com. They are quite good at diagnosing potential problems, but not so good in helping someone like myself resolve the problem.

So this is the failure:

One or more of your mail server(s) have no DNS (PTR) entries. RFC1912 2.1 says you should have a reverse DNS for all your mail servers. It is strongly urged that you have them, as many mailservers will not accept mail from mailservers with no reverse DNS entry. The problem MX records are: <edited out IP>.in-addr.arpa [No reverse DNS entry]

I'm running a Rackshack unmanaged server with Ensim. I have tried adding a PTR through the BIND Configuration | Zones | domain.com listing, but it keeps failing.

Thanks.

abrazell

Just submit a trouble ticket for Rackshack to set a reverse lookup for you, it has to be done on their end.

Provide your IP and tell them what you want the reverse lookup to be.