Postfix reject unknown recipients

[jjrowan]

I've been googling and searching postfix forums on how to reject e-mail addressed to particular user with no luck.
An account has been receiving 50 to 100 messages per day from various .icu domains. That user tried opting out (never opted in) but had no effect. The user has been given a new e-mail address but e-mail addressed to his old one is accepted by postfix and sent to the user. I don't understand how postfix is taking in e-mail and routing it to different user. I need to reject e-mail addressed to user@domain but can't figure out how to do that in postfix.

[TrevorH]

You can probably use /etc/postfix/header_checks. I reject mail that loops from our ticketing system to other people's using something like

Code: Select all

/^From.\ .*noreply\@spammy.co.uk/ REJECT

You'll probably want to look at ^To not ^From. And you have to postmap the file and main.cf needs an addition to activate header checks at all.