RE: Spammers using a non-existant address as return-path

["Costas Magos" <kmag@lab.epmhs.gr>]

> But, is there something I _should_ do in this situation, like 
> including 
> 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
actions. 

I suggest not enabling the verify command.

Hope I helped a bit.

~kmag