It's a great basic tutorial! Love it!

For convenience I'm trying to set domain forwarding, or how should I call it...
I want all mails to example.com to go to the respective user @example.net
Example:
bob@example.com->bob@example.net
john@example.com->john@example.net
/dummy@example.com->dropped/
but without doing it by hand in forwardings table.
Is it impossible, or it's just me not able to figure it out...