Verifying incoming addresses

I am thinking of using procmail to verify the return address of 
each incoming mail message.  I could write a script that 
procmail calls for each From line.  If nslookup fails on the 
return address, send the message directly to the trash can.

This cannot be a new idea.  Has anybody implemented this on a Unix
system?  If so, would you care to share the solution?

Frank Evan Perdicaro, KF6JGX            Dainippon Screen Engineering of America
BSP, MSCE; old GMC, Chevy&Hawk w/V        3700 Segerstrom Ave
inhouse: frank(_at_)server, x1258                    Santa Ana CA
outhouse: frank(_at_)dsea(_dot_)com, 714-546-9491x1258   92704       DoD:1097