Jeff:
> It took me a while before I could test this. The recommended solution
> succeeds at blocking the specified aliases when relayed through our
> gateway, but it does not do so at the SMTP level. It generates bounce
> notifications, which in the end will create back-scatter. The bounce
> message I got in testing gave an error code of 554.
Sorry, reject_unverified_recipient does not generate backscatter.
If you believe this is not so, then you need to provide actual
evidence so that we can point out your mistake.
Wietse
