[Mailman-Users] duplicates

Mark Sapiro mark at msapiro.net
Wed Oct 21 02:40:25 CEST 2015

On 10/20/2015 04:45 PM, Marco Stoecker wrote:
> I see a pattern now, when duplicates occur and it may have to do with
> mailman.
> If someone in a list send an email to two or three lists on the same
> server, the recipients of the list will get two or three times the same
> email. If it is sent to one list only, no duplicate occur.
> Any glue what the root cause could be?

If you are saying that people who are members of more than one list
receive a copy from each list of which they are a member when a post is
sent to multiple lists, that's the way Mailman works.

I.e. If I am a member of list1, list2 and list3 and someone posts to all
three lists, I will receive a copy from each list.

The list member setting "Avoid duplicate copies of messages?" (nodupes)
does not affect this. It only affects whether I receive a list copy if I
am also a To: or Cc: addressee of the post.

The list's Non-digest options -> regular_exclude_lists can modify this
behavior somewhat. E.g., if the regular_exclude_lists setting for
list1 at example.com includes list2 at example.com and list3 at example.com and
the regular_exclude_lists setting for list2 at example.com includes
list3 at example.com, then a member of all three lists will receive a copy
of a post sent to all three lists from only list3 at example.com.

regular_exclude_lists need to be set up with care. In particular, if
list2 at example.com is in list1 at example.com's regular_exclude_lists,
list1 at example.com MUST not be in list2 at example.com's
regular_exclude_lists or a post sent to both lists will not be received
by anyone who is a member of both lists.

Note that in the above, member means non-digest member. Digest members
are not affected by this.

Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan

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