Postfix to forward to Exchange if the user account does not exist
My College, unfortunately has purchased a product that requires a Microsoft Exchange server. What we're looking to do is set up our Postfix system to forward email that is going to accounts that don't exist over to our exchange server.
I have tried the luser_relay, and that does not work. I have also tried the smtp_fallback_relay, but haven't been able to get that to work either.
What were looking for is something like this...
email --> postfix box --> if there *is* an account, then deliver locally
email --> postfix box --> if there's no account, then forward to exchange
Anyhow, I've done some further research on it, and can't seem to get turned in the right direction. I'd appreciate any help or pointers to get me started. I can make the main.cf/master.cf available on request.