WTF..Someone's using my domain name to send spam!!!!

[natalie]

Hey guys, this problem can occur from a bot using your cgi mail program. If you look through your server stats you may find it and be able to prevent it. It could be in /cgi-bin/formail.pl or something similiar or in cgi/sys a server one that you can't access. If its in your server one then you can contact them to sort it out.
I don't know much about it, just that punaniman (my long suffering other half) had this happen to a client. Someone here should know more.