hi all,
i found the following article interesting,

Cutting the tcp/ip network connection with cutter
Cutter is an open source program that allows Linux firewall administrators to abort TCP/IP connections routed over Linux based firewall. Very handy to terminate connection such as SSH tunnels or VPNs left by our own users, abort crackers attacks as soon as they detected, kill high bandwidth consuming connection, or kill peer-to-peer traffic.
for full article: http://www.cyberciti.biz/nixcraft/vi...ction-with.php

Thanks