Email Filtering on MacOS X with fetchmail and procmail

What is procmail?

Oh, my, let's talk. =^ ) What procmail does is filter email, that's all it does, and it is incredibly powerful. It can do pattern matching, weighted scoring, blacklist lookups, re-write headers, and pipe its output to other programs for further processing. There are effective spam protection services written entirely in procmail and updated on a regular basis (i.e. www.spambouncer.org). If that's not enough, when configured just so, procmail can do fun email bouncing tricks. Nothing like it exists in the Windoze or Macintosh world. You need it. Let's get started.