Postfix + MySQL + fetchmail tweaks

[Cyberwizzard]

Hi everybody,

I've used the Vmail host guide to set up a virtual mail host:
http://www.gentoo.org/doc/en/virt-mail-howto.xml

This host is running for the same domain as the server - this is because I don't want local users to receive mail, only virtual users. This seems to work fine. However there are 2 little glitches that I need to get fixed.

First, when trying to deliver to Postfix with an invalid target address, Postfix accepts the mail and then immidiately bounces it. This has the disadvantage that spammers can drop the mail on my machine while it is bouncing and when a hoax return address is provided it'll bounce to that address. So how do I tell Postfix to refuse the mail the second it tries to specify an invalid target address?

And second, I've used a setup with Cyrus IMAP before switching to Courier. Now I've always used fetchmail to grab mail from 4 other POP3 accounts and deliver it to Cyrus which sorts it using Sieve in the correct folder. For some reason I can't find if Courier has a similar way to deliver fetched mail. I've tried using it as it is but then Postfix accepts the new fetched mail and then drops it into a local mailbox (one that should not be active in the first place as this system should use virtual users only). Is there a way to deliver it to Courier using IMAP? Or can I tell Postfix to accept the foreign address and drop it into a local account? Or is it possible to get fetchmail to deliver the mail to a certain account?
I've read something about using fetchmail directly to drop mail using one of couriers internal programs - however multiple sites warned me that its possible that fetchmail doesn't detect errors during delivery and simply removes the email from the remote host while it hasn't been stored locally.

[Cyberwizzard]

[/code]I've tailed the postfix logs and none of the local checks match, I'm posting a dump from the last part at which I entered a "RCPT FROM bala@bla.com" and postfix gave me a thumbs up with a 250 code: