email issues

[Charlie2009]

I recently migrated a couple of forums from one server to another. Before I switched over the DNS I ran the diagnostic test for email. The emails were received correctly. Once migrated I received subscription updates and PM notices as normal. However, it has become apparent that many of our users are not receiving email.

My first thought is SPF, the newly created domains got SPF records by default. During the server migration the mail servers were switched to google apps. So the SPF records would be incorrect since our mail is coming directly from the server and not google. I know that some (if not many) hosts do not honor SPF checking, so it makes sense that some users get mail and others do not. I have removed the SPF records as an immediate solution, i just don't know what the TTL is (DirectAdmin doesn't show it in a place that I know about). I switched the webmaster email to an address originating from a domain that I know doesn't have an SPF record associated, but the behavior doesn't appear to be any better. The headers show a SPF neutral result.

I am a little new at these types of email issues (especially on linux), and was wondering if anyone else has ideas on what could be causing these issues? I have already directed users to check spam folders and the mail is not there. The server admin (I am a dev) is looking at mail logs but hasn't gotten back to me yet. The administrator has also noted that registrations are down which could be stemming from registration emails not going out to everyone.

I appreciate your time,


EDIT:Here is a message to one of the users that doesn't receive email:

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

XXXXXXXXXXX@aol.com
SMTP error from remote mail server after end of data:
host mailin-03.mx.aol.com [205.188.109.56]: 421-:
(DNS:NR) http://postmaster.info.aol.com/errors/421dnsnr.html
421 SERVICE NOT AVAILABLE: retry timeout exceeded

So it looks like reverse DNS is the issue.

[ssslippy]

Yes AOL now requires a reverse DNS record. This is a recent change and we are currently suffering from this issue. Depending on who or what controls your DNS you may need to contact your host.

[Marco van Herwaarden]

Did you check that HTML AOL is returning in the email error message? It is explained on that page.