How to get Postfix working alongside Microsoft Exchange.

Hello,



I have an existing Microsoft Exchange 2000 Server with 150 users, I would
like to add a new Postfix Server to my domain and add all the new mailboxes
on this server from now on.



The Exchange server will not be replaced with Postfix, Postfix Server and
Exchange must work together. Both servers should serve the same domain.



The configuration should be:

1. Postfix server should receive the mail from the Internet.

2. If the recipient mailbox exists in Postfix Server then mail should be
delivered to the local mailbox in Postfix.

3. If Postfix does not hold the mailbox for the received mail then the mail
should be forwarded to Exchange.



Exchange will be configured to deliver mail to Postfix Server if the
recipient does not exist in Exchange.

Postfix and Exchange should work together, some mailboxes with be in
Exchange the rest in Postfix. Both servers will server the same domain.

How can a loop be also avoided when both server work togather?



Clifford