[GRLUG] Email and backscatter

[Michael Mol]

So, with Rosetta Code, I have a setup which looks like this:

Google Apps -- holds the MX records for the domain, forwards all email to me.
Web server -- has a mailserver which emits system emails.

Some time in the last few weeks, I started receiving backscatter from
badly configured mailservers.

1) Some spammer drops my domain name in the From: field
2) Mailserver receives email from spammer
3a) Mailserver flags email as spam, bounces it back at me (yes, I've
received at least one of these...)
3b) Mailserver delivers spam to destination inbox, and someone's
autoresponder bounces email back to me.

I don't imagine I can do anything about the 3a case, but I'd like to
do what I can about getting the forged messages properly marked as
spam.

In addition to SPF (which I'll be applying), what other techniques can I apply?
-- 
:wq