[plug] Mail Filtering

[Leon Brooks]

On Wed, 28 Aug 2002 16:04, ryan at is.as.geeky.as wrote:
> How does such a procmail script confirm that the message REALLY came from
> callen at corpus.wa.edu.au?

Sends a confirmation message back with a random magic number in the subject, 
and expects a reply with the same number within a certain timeframe.

If you're doing serious (Alice and Bob) stuff it gets more complicated.

Cheers; Leon