Watch out for relay attempts on your account via formmail.pl.
I just happened upon the following entry in my server log a few minutes ago:
126.96.36.199 - - [21/Aug/2001:00:07:23 -0400]
404 1938 "-" "SSM Agent 1.0"
(I've folded the single line over several lines, since it is so long.)
I've already reported this miscreant to email@example.com
for abuse on my server.
I don't use formmail.pl on my site anyhow, so they couldn't get any joy from me. I use my own script
Anyhow, watch out for this type of stuff!