-rw-rw-r--   1 nelson   nelson       1078 Dec  5 17:07 README
  -rw-rw-r--   1 nelson   nelson        170 Dec  5 17:04 age-smtp
  -rw-rw-r--   1 nelson   nelson        786 Dec  5 17:03 checkpassword.patch
  -rw-rw-r--   1 nelson   nelson        158 Dec  5 17:04 pop3-record

This set of programs watches POP connections, and for a period of time
thereafter, opens up the SMTP server for relaying from that host.  The
relaying is enforced by tcpserver and tcpcontrol.  Both programs are from
koobera.math.uic.edu/pub/software.  Look in ucspi-tcp for tcpserver.

The general plan is:
  o run pop3-record when a user authenticates.  This is done by
    checkpassword after patched with checkpassword.patch.  It puts an
    appropriate line to open up relaying into /etc/smtp.filter.newer
  o age-smtp is run every ten minutes by the crontab entry in root-crontab.
    It rolls over the opened hosts and rebuilds the database.

This is all in the public domain, and comes with no support.  It was written
by, and paid support is available from Russell Nelson <nelson@crynwr.com>.