I'm not sure if this can even be handled, but I thought I'd put it out there.
Someone is using our email address to originate spam. We are getting bombed with "Mail undeliverable" etc. messages from failed spam delivery attempts. This morning I check my inbox and found almost 100 of these since last night. I'm not sure what can be done about this. I'm a bit squeamish about just knocking this stuff out in procmail. Does anyone have any suggestions?