5a. procmail and email filtering resources
  SENDMAIL configuration to block unauthorized relaying
    <http://www.sendmail.org>
  Era Eriksson's procmail FAQ and resources site
    <http://www.iki.fi/~era/procmail/>
  How to make Netscape 2 and 3 filter incoming email
    <http://www.voidstar.com/voidstar/software.html#NSRoute>
  Mailshield (COMMERCIAL) server-based tool - works with a wide variety of email server
  software to help you reject spam, prevent unauthorized mail relaying and 
  halt email bombs
    <http://www.mailshield.com/>
  Other sites
    <http://www.acm.uiuc.edu/workshops/procmail/>
    <http://www.ii.com/internet/robots/>
    <http://www.ii.com/internet/faqs/launchers/mail/filtering-faq/>
    <http://www.samiam.org/spam/index.html>
    <ftp://ftp.informatik.rwth-aachen.de/pub/packages/procmail>
    <http://www.panix.com/e-spam.html>
    <http://www.cis.ohio-state.edu/hypertext/faq/usenet/mail/filtering-faq/faq.html>
    <http://www.ii.com/internet/robots/procmail/>

  Also consult the usenet news group comp.mail.misc

5b. Configuring your email client to show all headers
  Eudora Light Mac/Widnows, Netscape
  <http://help.mindspring.com/features/emailheaders/extended.htm>

5c. Deciphering headers
  <http://kryten.eng.monash.edu.au/gspam.html>
  <http://digital.net/~gandalf/spamfaq.html>
  <http://www.rahul.net/falk/mailtrack.html>

5d. Lists
  Paul Vixie's MAPS RBL (Realtime Blackhole List)
    <http://maps.vix.com/rbl/>
  Internet Blacklist
    <http://math-www.uni-paderborn.de/~axel/bl>
  MindSpring Spam Filter List
    <http://www.mindspring.com/cgi-bin/spamlist.pl>
  Rahul Dhesi's Block list
    <http://www.rahul.net/dhesi/nojunk.txt>
  Rogues' Lists
    <http://www.vix.com/spam/rogues.html>
    <http://math-www.uni-paderborn.de/~axel/BL/blacklist.html>

5e. Hunting/Tracking/Responding
  Sam Spade (FREEWARE) - excellent collection of IP tools for tracking sources,
  testing relays, and verifying DNS information:
    <http://www.blighty.com/spam/spade.html>
  Spam Hater (FREEWARE) - analyzes U*E and suggests reply addresses. 
  Works with many email programs:
    <http://www.compulink.co.uk/~net-services/spam/>
  Spam Blaster (COMMERCIAL) - compares incoming messages to UCE blacklist,
  deletes offenders:
    <http://www.gooware.com/software/ISOFT/SB/about.htm>
  Teergrube - hold SMTP connections open indefinitely (FAQ):
    English <http://www.iks-jena.de/mitarb/lutz/usenet/teergrube.en.html>
    Deutsch <http://www.iks-jena.de/mitarb/lutz/usenet/teergrube.html>