Other Random Possibilities
  Mail Example
  Procmail for mail delivery, pipes select incoming emails to a program.
  Program PGP decrypts message, extracts commands to run, sends results back to sender.
  Non-listening daemons
  Use libpcap/etc to sniff for correctly formatted incoming packets, and run local commands as appropriate.
  Commands may be used to modify ACLs, initiate outbound connections, etc.

Copyright 2003, Bri Hatch of Onsight, Inc.

Presented at SecureWorld Expo, 2003.

Presentation created using vim and MagicPoint.