[Mailman-Users] Bounce Processing Settings

Christopher Adams chris.a.adams at state.or.us
Tue Jan 24 18:41:44 CET 2006


Thank you for the reply. I think I understand it now. So, alot of the 
traffic related to bounces is being generated by spammers sending to the 
list-bounces addresses. I will also adjust the bounce processing for the 
little-used lists to cut down a bit on the interaction with actual 

Recently, I made a system-wide change so that all messages from 
non-members are rejected and a message sent to them. The reason I did 
this was because I didn't see a way to change the message sent to list 
owners when a non-member message was discarded. In a previous post, you 
mentioned that the newest version of Mailman allows that modification.

So, my question is- using my current settings, do rejection messages to 
non-members generate any bounce traffic? The logs show a message sent to 
a bogus user, but it seems to end there - no mailman log activity.

Christopher Adams wrote:

 >There seems to be lots more spam/bounce activity lately and I
 >am wondering if I should consider changing the way bounce behaves.

If you're thinking about 'unrecognized bounces' due to spam being sent
to the list-bounces address, your bounce processing settings won't
affect this.

Basically, spam gets involved in bounce processing in only a couple of
ways. When spam is sent directly to the list-bounces address, this
essentially always is an unrecognized bounce, because it doesn't look
like any known delivery status notification (DSN).

When spam is sent to the list address, and the 'post' is rejected or
held (say because the spammer is not a list member and the list
rejects or holds non-member posts), the reject/held notice often
bounces because the address that the notice is returned to is not
deliverable. This results in a legitimate bounce which may be
unrecognized because the DSN is not one that Mailman can parse, or it
is recognized as a bounce for a non-member address and ignored.

The list's bounce settings (other than
bounce_unrecognized_goes_to_list_owner) have no effect on any of this.

 >could easily change all lists globally using withlist, but I thought
 >that I would first see what others are doing.
 >For 'bounce detection sensitivity', I  am currently using:
 >5, 7, 3, 7

These settings are the defaults because they are reasonable settings
for most lists. If you are sensitive about sending too many messages
to dead addresses (AOL, e.g. dings you for this), and you aren't too
concerned about disabling people for 'full mailboxes', etc. you could
lower the threshold.

Also, for lists with low activity - e.g. one or two posts per week, you
probably want to both lower the threshold, and extend the 'stale
after' time.

Christopher Adams
Library Systems Analyst
Oregon State Library
503-378-4243 258
chris.a.adams at state.or.us

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