[Mailman-Users] Bounce message confusion

Robin Rowe rower at movieeditor.com
Sat Nov 19 00:40:55 CET 2005

Thanks to Dan and Stephen for the help with mailman bounces. I 
understand the overall issues much better as a result and am working 
with my ISP to try to track down the MTA problem.

I'm still puzzled in some details in how to configure bounce processing. 
If there's a doc somewhere that explains it better please let me know. 
On the website it says the docs are incomplete and outdated.

Dumb question, but I want to make sure I understand: if I turn off 
bounce processing what happens when there's a bounce?

My current settings, I have "The maximum member bounce score before the 
member's subscription is disabled" set to 5.0, "The number of days after 
which a member's bounce information is discarded, if no new bounces have 
been received in the interim" at 7, "How many Your Membership Is 
Disabled warnings a disabled member should get before their address is 
removed from the mailing list" at 3, and "The number of days between 
sending the Your Membership Is Disabled warnings" at 7. I have the three 
bounce-notifications-to-me settings turned on.

I interpret these setting to mean that it will be at least 5 days before 
a subscriber email address could be disabled and 3 more days until 
automatic removal. However, I've had a subscriber report that after 
rejoining my list he was unsubscribed again the very next day due to 
bouncing. Is that possible?

The mailman description for bounce processing (enclosed below) says, 
"You can control both the number of reminders the member will receive 
and the frequency with which these reminders are sent." It isn't clear 
to me how to control that from the settings offered. At what point do 
warning messages get sent and how often do subscribers receive bounce 
messages? How do I change the frequency and text of bounce warning 

My subscribers complain that they don't like to receive bounce messages. 
Can I stop their bounce warning messages but still keep getting bounce 
notifications sent to me? How?

It says, "You should tune both of these to the frequency and traffic 
volume of your list." For a one-way list of 500 subscribers who get a 
few announcements a week, how would I estimate what the right settings 
should be?

Thank you!



According to mailman:

When a bounce is received, Mailman tries to extract two pieces of 
information from the message: the address of the member the message was 
intended for, and the severity of the problem causing the bounce. The 
severity can be either hard or soft meaning either a fatal error 
occurred, or a transient error occurred. When in doubt, a hard severity 
is used.

If no member address can be extracted from the bounce, then the bounce 
is usually discarded. Otherwise, each member is assigned a bounce score 
and every time we encounter a bounce from this member we increment the 
score. Hard bounces increment by 1 while soft bounces increment by 0.5. 
We only increment the bounce score once per day, so even if we receive 
ten hard bounces from a member per day, their score will increase by 
only 1 for that day.

When a member's bounce score is greater than the bounce score threshold, 
the subscription is disabled. Once disabled, the member will not receive 
any postings from the list until their membership is explicitly 
re-enabled (either by the list administrator or the user). However, they 
will receive occasional reminders that their membership has been 
disabled, and these reminders will include information about how to 
re-enable their membership.

You can control both the number of reminders the member will receive and 
the frequency with which these reminders are sent.

There is one other important configuration variable; after a certain 
period of time -- during which no bounces from the member are received 
-- the bounce information is considered stale and discarded. Thus by 
adjusting this value, and the score threshold, you can control how 
quickly bouncing members are disabled. You should tune both of these to 
the frequency and traffic volume of your list.


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