[alwayzright]

That doesn't kill a source of spam. You probably just got an open relay shut off. I assure you it takes much more to stop a spammer. If you're interested enough to go that far, do some research on the Internet. Tracking spammers is fascinating because it never ends. The spammers always find some new way to progagate their trash.

[Keith in Iowa]

Let me say it in plain, simple English: Yes - SOURCES of spam have been killed as a result of tracing headers. I have personal knowledge of ISPs applying their terms of service agreements and terminating services to customers for violations of the TOS agreements. Need I explain any more?