I have about 3 knows email addresses in my domain, which don't exist and to which a lot of spam is sent. Some of this spam is pretty heavy, and I'm wasting a lot of traffic on it, so I don't want to even receive emails if their destination is one of those 3 addresses. Since I know that the users don't exist I would like postfix to reject emails during RCPT TO: negotiation. Basically, all I want is to update some config with those 3 addresses, and every email sent to them must fail to come in.

I want to stress out following:

• postfix works as a relay for domain, there is no local users
• postfix has no knowledge about validity of other emails within domain, so it cannot simply reject unknown recipients