[Mailman-Users] getting "mail forwarding loops"

Jeme A Brelin jeme at brelin.net
Wed Feb 28 11:53:39 CET 2001

On Wed, 28 Feb 2001, Bob Puff at NLE wrote:
> Running Mainman 2.01 with Postfix, with many different domains.  
> Occasionally when looking at the mail logs, I see a "Mail forwarding
> Loop" messsage for <listname>@machine.hostname.  Nothing seems to be
> out of the ordinary otherwise... I can go thousands of messages
> without seeing this, and other times I see quite a few.
> Could this be related to messages bouncing?  It's right in the log
> during a mass send, and almost looks like Mailman is sending itself
> the message.

I don't run Postfix on my mail server (though I do run it on my
workstation as a null client), but I had a similar problem with sendmail.

The messages for which I got those errors, however, were not delivering at
all.  You should doublecheck that.

The problem comes when your mail server goes to lookup the mail exchanger
for the domain the message is addressed to and finds itself, but the
server is not configured to accept mail for that domain...

Let's say your mail server is supposed to recognize crazyperson.net as a
local domain... but you don't have that configured properly.  A message is
then handed by a local client (mailman) to the server destined for the
(local, but unrecognized) domain crazyperson.net.

So it says "Hmm... where does crazyperson.net mail go? I don't recognize
it.  Lemme check the domain record.  Hmm... MX is
poopyshoes.crazyperson.net... and a quick nslookup says that's wait, I just sent that message and it came back to me...
but it said I just sent it and now I want to send it again... oh dear, I
hate being a dumb machine and unable to prevent this silly recursion!  I
should make a note in my log so the adminstrator can help me!"

Anyway, that's the best I can describe what was going on with me.  And
yes, I always give my daemons personalities.  You should hear my
curmudgeony NFS daemons.  lockd is particularly amusing.  And httpd thinks
he's pretty cool stuff, the little twerp.

I don't know what else might be causing your problem, but that's why I got
a similar message from sendmail.

Thank you very much for indulging an old woman in her failing years.
     Jeme A Brelin
    jeme at brelin.net
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