Re: Sendmail problem and comcast.net
On Thu August 7 2008 13:14:40 Account for Debian group mail wrote:
> We're having a problem sending mail to comcast.net. The message we are
> getting is:
>
> Aug 7 12:31:18 smtp sm-mta[22694]: m77JV1iC022684:
> to=<someuser@comcast.net>, delay=00:00:17, xdelay=00:00:01, mailer=esmtp, p
> ri=210588, relay=mx2.comcast.net. [76.96.30.116], dsn=4.0.0, stat=Deferred:
> 421 IMTA12.emeryville.ca.mail.comcast.net comcast Reverse DNS failure : Try
> again later
<snip>
> Anyone have any ideas? Does anyone have a phone number to get a hold of
> comcast.net administrators?
The problem is at your end, not Comcast's end. Your 209.102.124.32 server
lacks a reverse DNS entry (PTR record) with value smtp.gssf.org.
Most mail servers block or penalize incoming mail from "servers" with no
reverse DNS or where reverse DNS does not match forward DNS. 99.9% of such
cases are not real servers but rather hacked PCs trying to send spam. The
other 0.1% are real mail servers which by mistake or oversight have DNS
inconsistences - and they should be fixed promptly.
--Mike Bird
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