Exim setup help please

[Bill Horne]

Thanks for reading this.

I had a crash that caused me to revert to the vanilla setup files for 
Exim, and now I'm getting frozen messages due to spam.

Spam that arrives with an invalid address "should" be rejected, 
but Exim is attempting to deliver it, and then attempting to send 
a rejection notice to the "From" address, which is of course fake. 

I wouldn't normally worry, but some spammers hunt for machines that 
do this, and forge the "From" headers to get their spam delivered as 
a reject notice.

All suggestions welcome.

Bill Horne