Normally, Postfix will reject e-mail sent to non-existent users if a catchall isn’t present for the specific domain that is receiving mail. However, you can make a super catchall to catch any and all e-mail that Postfix receives for the domains in its mydestination list:

Add the following to /etc/postfix/

luser_relay = root
local_recipient_maps =

Then reload the Postfix configuration:

# postfix reload

For more information: