[Mailman-Users] nodupes flag

Mark Sapiro msapiro at value.net
Fri Dec 2 01:49:07 CET 2005

Young, Darren wrote:

>What / how exactly does the 'nodupes' flag do? That page says it 'tries'
>to filter out duplicate messages to users, how does it determine that 2
>addresses are in fact the same person?

It doesn't. That's not at all what it does.

>And on that, if I have 1 member
>on a list with 2 addresses (same person), say jane.doe at mydomain.com and
>jane.doe at yourdomain.com and the nodupes flag is on for one or both of
>them, will Mailman in fact not duplicate the message to those 2 member


>Reason is, we're in the middle of converting from one domain name to a
>new one and would like to leave the old address as well as the new
>address in every list for a period of time. Then, after this time
>passes, remove the old member address. However, I don't want people to
>start receiving duplicate messages and was wondering how exactly this
>flag works.

All nodups does, is when figuring the recipients for a post (not a
digest), if a particular member's address is found in To: or Cc:
headers of the post and that member has nodups set for the list, that
member will not be sent a copy of this post. This is all explained
under "Avoid duplicate copies of messages?" on the user options page.

In other words, If you have nodups set on your mailman-users at python.org
subscription, you will only receive this post directly from me and not
from the list since your address is in To:.

>I'm currently planning to migrate people to the new domain via a
>clone_member command for every member of every list. Have a script dumps
>out the current membership for a list and if the domain portion is the
>old one it does a clone from user at old_domain to user at new_domain. I added
>the -r flag to the clone_member command to remove the old address but
>have been asked to see if we can maintain the multiple memberships
>without people receiving dupes.
>Any feedback would be great. Thanks.

You can set the old_domain subscription mail delivery to 'disabled'
(nomail in the admin membership page). Then members in both domains
will be able to post from either, but will only receive at new_domain

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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