Mail routing and MX records: trouble

Barry Margolin barmar at
Mon Oct 22 17:28:31 UTC 2001

In article <9r1i5q$661 at>,
Steve Linberg  <slinberg at> wrote:
>In article <9r1efn$5ln at>,
> Simon Waters <Simon at> wrote:
>> Steve Linberg wrote:
>> > 
>> > who bounce it because a reverse lookup of the
>> > sending domain "didn't work".
>> > Assuming it's not a DNS configuration error somewhere on their part, is
>> > there anything wrong with the above that I should fix?  Or is there more
>> > detail I could provide that would help diagnose the problem?
>> If you want us to help diagnose the problem the real domain and
>> IP address would be really helpful.
>Absolutely.  The IP is; the domain is, and 
>the subdomain running the MLM and being rejected by the handful of 
>domains (actuallly just two: and is 
>  (I've also written to postmaster@ those 
>domains, no response so far.)

Your DNS looks pretty OK to me.  The only potentially problematic thing I
noticed is that your nameserver identifies itself as when I connect to its SMTP port, and I assume it
sends the same name in its HELO message when it's sending outbound mail.
This name resolves to your IP address properly, but the reverse DNS
resolves to

Servers aren't supposed to do this much checking of the HELO hostname,
precisely because of problems like this or because the server might be
multi-homed (so it has address A.A.A.A and B.B.B.B, makes a connection
whose source address is A.A.A.A, but the HELO contains a name that resolves
to B.B.B.B).  But some sites have enabled extremely paranoid checking on
their SMTP servers.

So try configuring your server to send "" in its
greeting messages.

Barry Margolin, barmar at
Genuity, Woburn, MA
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.

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