I was wondering if anyone had any experience using postfix to redirect
incoming Internet mail for 2 separate Groupwise backends. A part of our
organization that has always been separate from us (different mail domain,
different groupwise system) needs to have their mail domain intergrated
into our own. Let me explain further.

We have two mail domains, @ourdomain.com and @theirdomain.com right now
Postfix is only handling @ourdomain.com and it is passing it off to our

The goal is to have Postfix accept incoming mail for both our and their
domain and route them to the appropriate Groupwise system. Now if it was
that easy I would just use a transport map to sort the mail. The catch is
that because all the users on both mail systems have unique user ID's they
want the sorting to key off of usernames and not domain names. So that
joe@ourdomain.com and joe@theirdomain.com both get delivered to the same
mail system. They basically want everyone on their system to have the
ability to use either our or their mail address domain. (and people in hell
want icewater was my first reaction, but then I was reminded about the
salary continuation program)

Now I could again achieve this using a transport map or virtual alias table
on Postfix. The problem is we are talking about 4000+ users. I don't want
to manually maintain an 8000 line virtual alias or transport map. (4000
actual addresses plus 4000 alternate addresses)

So I thought about LDAP. I think Postfix can reference an LDAP server to
find out where to deliver an email. The problem is we will have 2 LDAP
servers because not only do the other Groupwise folks have their own
Groupwise system but they have their own eDirectory tree as well that is
totally separate from our own. (It keeps getting better and better, no?)

So with all of this background info. I was wondering if anyone knew offhand
if Postfix could reference two separate LDAP systems. If so if someone
could point me to some documentation/cool solution on how to configure this
I would be eternally in their debt. Or if someone could suggest an
alternative method of achieving this goal that did not include me having to
manually edit a text file each time a user on either system was added or
deleted I would really appreciate it.

Kennon Keoseyan
Management's Whipping Post/Linux Sysadmin

PS: I tossed around the idea of exporting both eDirectories into LDIF's and
then importing them into one OpenLDAP or NLDAP server for Postfix to
reference but then there are synchronization issues to deal with. Does
anyone think this is a good idea?