Overview
========
This program is designed to process requests for email addresses to be
appended to the Remailer Abuse Blocklist.  It expects to be passed an email
address or an email from which to extract a sender address.  This address is then
confirmed by way of a Challenge Response.

The program relies on the following files:
  Python Scripts
  ==============
  rab.py          Main Python program

  Text files
  ----------
  All of these filenames (and paths) are configurable in ~/.rabrc
  request.txt	  An Email payload to send with confirmation requests
  duprequest.txt  Email payload for duplicated requests
  failed.txt	  Email payload for failed requests
  success.txt	  Email payload for successful block requests

  Database files
  --------------
  All of these filenames (and paths) are configurable in config.py.
  request.db      New RAB requests
  dupcheck.db     Duplicated requests
  master.db       The RAB database
  All database files are of BerkeleyDB format.  In all three the format is
  identical:
  Key:Email Address    Data:Timestamp

  Web Interface
  -------------
  rab.html        Plain HTML file describing use of the RAB
  rab.cgi         CGI interface for submitting addresses

Duplicate Checking
==================
This program includes duplicate checking functionality to prevent repeated
requests from being used as a means to annoy/flood a 3rd party.

When a new request is submitted, the address and timestamp are inserted into
the requests database.  If this address is resubmitted, it is responded to and
inserted into the duplicates database.  Further resubmissions will receive no
further responses for a configurable period of time.  Correct challenge
responses will be processed.

Format of rab.blk file
======================
The rab.blk file contains email addresses, one per line.  A configuration
option enables the file to be written with hashed output instead of plain text
in order to prevent address harvesting.  Processing of this hashed format
requires a planned update to Mixmaster.