[Mimedefang] Detect mail loops in mimedefang ?

Mark Suter suter at zwitterion.humbug.org.au
Thu Jul 28 08:36:06 EDT 2005

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> First I wanted to check the Received: lines and count every line where
> one of our mailrelays is in. If the count reaches a specific value drop
> the mail. The Problem is, that the Received-lines are written new if the
> message is bounced.

Sendmail has been counting Received: lines for ages - that's the
mechanism behind the maximum hop count:


> Theoretically I have to check the whole message for this Received: lines
> ? Or is there another possibility to check for looping mails ? 

Theoretically, a mail loop may exist yet be undetectable.  In
practice, this theoretical possibility doesn't matter and
sendmail's maximum hop count is enough.

I would caution you against spending too much effort protecting
about an unlikely event; however, it may be that it has happened
to you recently.

Yours sincerely,

- -- Mark John Suter  | I know that you  believe  you understand
suter at humbug.org.au | what you think I said, but I am not sure
gpg key id 2C71D63D | you realise that what you  heard  is not
mobile 0411 262 316 | what I meant.        Robert J. McCloskey
Version: GnuPG v1.4.1 (GNU/Linux)
Comment: Check Keyservers or http://zwitterion.org/keys/


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