Grelying and automatic forwarding

[Dave Smith]

I setup postgrey last week and it has clobbered mountains of spam. I am 
very happy with it. However, I have one problem. I have several old 
email addresses on servers I don't control (byu.net, cs.byu.edu, for 
example), that I have setup to forward to my current email address 
(thesmithfam.org). However, they also forward spam. This is a problem 
that greylisting can't solve. Any ideas? I guess I could go with 
SpamAssasin, but I had hoped to avoid that because I don't want to spend 
time training it.

--Dave