I'm sure this can't be the first time this has come up, but my google-foo just isn't strong enough to find what I'm looking for. Here's the scenario:
Postfix is final destination for domain1.tld, and is implemented as virtual mailboxes (no local unix accounts), with mysql lookups. So far so good, and that's easy to setup. u...@domain1.tld either gets delivered to the local mailbox, or rejected. Now the wrinkle: if u...@domain1.tld doesn't exist, RELAY to u...@domain2.tld (same user in a different domain). domain2.tld exists on another server and the databases are NOT shared. I've setup an entry in virtual-alias-domains so that @domain1.tld returns @domain2.tld. It's my understanding that should cause u...@domain1.tld to be mapped to u...@domain2.tld according to the virtaul(5) readme. That didn't seem to be working, so I thought "well maybe it's because I'm not a delay for domain2.tld", so I setup a relay-domains entry that says I'm a relay for domain2.tld (again, all of this is driven by a mysql database). Whenever I send mail to u...@domain1.tld (where a mailbox actually exists), the mail gets delivered exactly like I'd expact. Whenever I send mail to us...@domain2.tld, it bounces with: 'Recipient address rejected: User unknown in virtual mailbox table' Is what I'm attempting to do even possible? Also, I really don't want to become a backscatter source. Can I turn on address probes for this one domain, or is it pretty much on for everyone? Thanks in Advance!