what actually happens with rejected mail?

[Chuck Swiger]

Marco Beishuizen wrote:
[ ... ]
> Everything is working fine, but now I wonder what happens with the
> spammail that is being rejected? Are those spammails being deleted? Or
> are they send back to my ISP? My maillogfiles show that spam is
> correctly filtered, and a message with the errorcode is send back. But
> who else is seeing those errormessages?

Probably nobody.  Normally, when your mail server rejects an incoming message 
with a 5xx, the sending MTA is supposed to generate a DSN to the sender, letting 
them know that their attempt to mail you failed (with the reason you gave).

In the case of spam, that address is typically forged and the spamware MTA may 
well simply drop the reject.

-- 
-Chuck