In message <Pine .
"John R Levine" <johnl @
>> > For purposes unrelated to mailing list administration, I have
>> > developed a C language program whose purpose is to automatically
>> > differentiate automated response e-mail messages (e.g. bounce
>> > messages) from other types of e-mail messages.
>> Bounces have the unique quality of have a null return envelope.
>> Filter on that and you'll have no problem. (
>In theory, you are entirely correct. In practice, the variety of broken
>bounces staggers the imagination, and you need to catch all sorts of
>garbage and do complex pattern matches to try and figure out what
I would agree with what John has said, except that I would remove the
Nothing I'm doing in my automatic response recognizer/differentiator is
particularly complex. I'm not even using regular expressions. Just
plain old verbatim text matching against the Subject: line and the first
several lines of body text.
The only complex part is the painstaking work of analyzing hundreds of
thousands of bounce and non-bounces mail messages and coming up with
the list of `stigmata' strings (that are distinctively found only in
bounce and autoresponse messages) to search for.