The mailing list for listmasters using Sympa

[Aumont - Comite Reseaux des Universites <address@concealed>]

Adam Bernstein wrote: However, note that the "rate" is not the same thing as the

number of bounces -- it's a number calculated internally,
based on the number and type of bounces, according to some
formula of Sympa's that I do not know.  So I don't know what
rate you would have to use to represent two hard bounces,
for instance.

Perhaps Serge will be able to comment further.
  

Your are right. Sympa's euristiq to remove subscribers from list is not only based on the number of bounces. The number of bounces is not a decisive information : it depend on the list traffic and the type of  non delibvery report. Let's say :

• on a list with one mail per week, 3 or 4 bounces "user unknown" is a strong indication to remove the related address.
• on a list with one mail every 30 minutes (sympa-users :-) 20 bounces "mailboxe full" is just an indication that the subscriber is tired to check his mail :-)

In addition, old delivery reports have to be forgotten by the system (if they are somme traffic and 0 bounce for a particular email during the following week, we sould probably remove all bounce history for that  particular email.

The goal is not to remove all emails with errors but just to keep the bounce rate under a reasonable limit. On our national mailing list service the bounce rate of many list was about 20% / 25% before using automatic deletion. Now, the typical bounce_rate for the same lists is 3% / 5% (2.5% for sympa-users). This result comes with Sympa's default parameters, but you can make Sympa more or less reactive with bounces using  We never or nearly never receive complaint about unwanted unscubscribtion. A low bounce rate help for a faster message distribution keeping less messages in outgoing sendmail spools.

If you want more details have a look at Sympa's documentation or .... Sympa sources starting with task_manager::get_score .

Serge

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