RE: Spammers using a non-existant address as return-path
> But, is there something I _should_ do in this situation, like
> some text in the bounce saying that this address has never
> existed, and
> is being abused by spammers? If yes, _how_ should I do it?
I don't know what exactly you should do, i am not aware of the best
practices about this matter, but I guess informing people that you not
the one to blame is not a bad idea.
You can use the following line in your configuration file:
receiver_try_verify = true
in order to attempt to verify addresses before accepting mail. In this
case all mails for invalid users are rejected and no bounces are sent.
Take a look at the vacation package; you can set an autoresponder with
it (though I am not sure you can configure it to alter a bounce).
Another program you might find useful is mailagent with which you can
set filters to catch mails for any unknown user and take appropriate
I suggest not enabling the verify command.
Hope I helped a bit.