Have found in my postfix logs where someone is sending one email to alot of non-existant users. This domain is not on the local machine. Thus, this machine accepts the mail and attempts to deliver it.
If the domain in question is not on your server, why is it trying to deliver the mails? That would make this server an open relay and you should fix that ASAP. Or maybe I'm missing the context here??
Regards Ralf G.
