Postfix: how to block incoming emails to a specific recipient?

Question

I have Postfix set up to deliver all incoming email to ⟨any_random_address⟩@mydomain.com to [email protected]. I've recently noticed that a large percentage of spam is going to the same non-existent username, and I'd like to block incoming email to that username, while still sending all other emails to my inbox. What is the best way to accomplish that?

Answer 1

Aside from the fact that catch-all doesn't really make sense:

In your virtual aliases map (e.g. /etc/postfix/virtual_alias_maps), add the following line:

[email protected] devnull

In /etc/aliases, add the following line:

devnull:  /dev/null

This defines a mailbox named devnull and stores its contents in /dev/null.

Don't forget to update the alias caches and restart Postfix, for example like

sudo postmap /etc/postfix/virtual_alias_maps
sudo newaliases
sudo service postfix restart

Now you should be fine.