Post migration mail routing

[pisanq]

I'm using the trial edition 60days of ZCS Network Edition
We are in the middle of migration from sendmail to Zimbra. During this migration phase, I want to make sure our end user can reach both sendmail and Zimbra simultaneously. I got two problems now:
1) How to make sure all outgoing mail from Zimbra, to local domain also copied to our old server Sendmail for each account respectively. eg:
our domain example.com, our old server running sendmail mail.example.com and our zimbra is zimbra.example.com
Every time user1 send email from Zimbra to user2@example.com, user2 can read that message in both sendmail and zimbra server.

2) We have two domain hosted on sendmail, by using OpenWebmail the domain will be choosen automatically based on the URL address of the end user use when accessing the system. eg:
user@domain1.com use http://mail.domain1.com to access OpenWebmail
user@domain2.com use http://mail.domain2.com to access OpenWebmail
So when a user composing an email, the mail from column will automatically detected based on the URL use either from user@domain1.com or user@domain2.com
How to achieve this in Zimbra?

Thanks for this great product!

[phoenix]

You should set-up a Split Domain for your configuration.

[pisanq]

From what I understand, Split Domain can be use if some users are migrated and the rest still not. In my situation, all 100% users from sendmail has been migrated to Zimbra. Currently all users in sendmail have alias to zimbra.domain.com server so any incoming email (locally in sendmail system or from internet) will be stored in sendmail server and zimbra server. So there is no problem if the user use old mail server to send an email (from OpenWebmail interface only) to any local users because they have alias to zimbra.domain.com to ensure message will be stored both in old mail server and on zimbra server.
However, when user send an email from Zimbra (by using any web interface, POP3, IMAP, mobile devices etc), Zimbra will send those message locally to zimbra mailbox only (because all users has been migrated to zimbra), leave the old sendmail server without any copy of it. The recipient who just check openwebmail interface won't know there is new message for them.

Alternatively (if there are no solution to route mail from zimbra to local user via old mail server during migration), I'm planning to install OpenWebmail interface (during this few months migration phase only) on my zimbra machine so the end users can choose to check their email via OpenWebmail or Zimbra.

We will remove the entire sendmail and OpenWebmail at the end of this migration phase when all users already familiar with Zimbra:-)