[exim] Forged FROM

Hi everyone:

I'm not sure what, if anything can be done about my situation. One
spambot is forging my email address and IP in their FROM headers, so my
email server is getting hammered with bounces.

I've checked and I'm not running an open relay, and the emails are not
originating with me but the bounces are coming back from pretty much all
over the world, sometimes several dozen per minute.

I don't think there's anything I can do except ride this out but it's
really starting to annoy me. Since I never see the original emails,
only the bounces with the forged FROM info, I can't even figure out
where this is coming from.

Any ideas other than suck it up?