R Lists06 wrote:
Have you considered changing your setup to reject emails in the smtp process if they do not have a valid rcpt to? i.e. a valid email address on your machine to accept them?
This will eliminate much of what you are experiencing...
Well I'm willing to consider it. The problem is that the 'primary' MX for most of the inbound-relayed domains is a barracuda anti-spam device which talks to a Exchange server through a secret-handshake pipe I can't get at from the secondary.