I used the split-domain doc to set things up as I have them (well, plus the multi-server install doc first.) The SD doc explains the logic quite well and addresses the functions to make things work overall but it missed some specifics (in my view.) Of course my view is warped and often wrong.
For example I'll demonstrate some flow issues with SD I ran into -
example.com DNS MX=mail.example.com (consider this our current iPlanet)
mail.example.com accepts all mail for example.com.
foo@example.com bar@example.com
Now I want to add Zimbra into a SD config with mail.example.com first and the new zmta.example.com as a secondary destination.
*This requires no DNS changes (or should it have?)
* zmta.example.com will accept mail for example.com and forward over to
mail.example.com if the user isn't found.
* mail.example.com will have a per-user forward set to zmta.example.com (but NOT
user@zmta.example.com because postfix routes that to local users on zmta.example.com)
So the question came down to...how to forward someone's mail from mail.example.com to zmta.example.com *all* for email addressed to
user@example.com ? I'm explaining it poorly but I believe that along with all of the above I need to create a domain alias (migrate.example.com) on zmta.example.com which is aliased to example.com on zmta.example.com.
*whew*
The result being, on mail.example.com I set a forward for user "foo" to
foo@migrate.example.com (with an appropriate MX record for migrate.example.com->zmta.example.com) which will route the mail and then (because it's an alias) flip the mail to
foo@example.com on the zmta.example.com server.
Am I re-inventing the wheel here or am I clunking along on square wheels because I missed how to round them out?
Thanks,
Doug