MAILER-DAEMON spam

I get a lot of bogus MAILER-DAEMON messages these days, either from unsuccessful spam attempts which used my domain in the From address, or as a clever trick to send me spam. That led me to have this great idea (drumroll, please):

Why can't my mailserver remember what mails it actually sent, and figure out which bounce messages are legit? Bogus MAILER-DAEMON messages would get dropped on the floor. Optionally, three bogus ones from the same address could cause that address to be blocked.

Seems straightforward enough to me ... what would be the problems with doing that?

Trying to figure out IIIMF

I have installed the iiimf-htt-server and iiimf-htt-le-newpy packages, which are parts of the Internet/Intranet Input Method Framework. I want a Simplified Chinese input method which will allow me to send mail from Mozilla, and these packages ... hmmm ... are somehow related? I've been looking all over for documentation, though, and I can't figure out what the heck I need to do. It's possible I need to use a Chinese locale to get use the Chinese input method, but I certainly don't want to do that.

Does anyone know anything about this stuff?