[Mailman-Users] Mailman - majordomo in cascade

Mark Sapiro msapiro at value.net
Fri May 13 23:27:47 CEST 2005

>Oliver Schulze L. wrote:
>>I have this question:
>>There are 2 list, mine and another one in majordomo.
>>I want that if someone post an email to the majordomo list, a copy
>>is sended to my mailman list.
>>It would be like my list is subscribed to the majordomo list.
>>I worry about duplicating email and infinite loops, thats why
>>I have not tested it yet.

Caveat: I don't know majordomo.

You can subscribe your Mailman list to the majordomo list. So far there
is no loop. Your issues are:
- users who are members of both list get duplicates of posts to the
majordomo list.
- you have to set up your Mailman lists to accept the messages from
majordomo. This can be tricky. You may need to subscribe the "envelope
sender" of the majordomo list to your Mailman list with delivery

>>If this works, then it would be nice to implement the other way:
>>if someone post in my mailman list, a copy is sended to the majordomo list.

Now you have the complement of the above situation plus a potential
loop. Mailman adds an X-BeenThere: header with the list address in it
to prevent looping. Thus when you post to Mailman and the post goes to
majordomo and then comes back to Mailman, the X-BeenThere: will
prevent it going out a second time *provided* that majordomo hasn't
munged it.

Assuming majordomo does nothing to prevent looping (I said I don't kmow
majordomo), the above works for a post to Mailman, but a post to
majordomo would go to Mailman and be sent to majordomo a second time
and go out from majordomo a second time before being discarded by
Mailman because of the X-BeenThere:.

If majordomo has loop prevention that doesn't conflict with Mailman
(Mailman is OK with multiple X-BeenThere: headers), then there should
be no loops.

The worst possibility is if majordomo has no loop protection *and*
strips Mailman's X-BeenThere:. Then you'd have an infinite loop.

You need to check this with someone who knows majordomo *and* test it
first with small test lists.

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

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