IPS

I'm not sure if that is what your looking for. I installed shorewall and my linux box now acts as firewall/DMZ/DNS Server (Powerdns)/VPN Server(OpenVPN). When I get enough diskspace I'll probably include a Squid Proxy Server. So far it works well...

You can also use snort for this ( http://www.snort.org/ ). It's an
IDS (Detection System), but it has hooks that make it responsive
so if, for example, it detects your being attacked in some way it
can adjust firewall rules to prevent further attempts. It can be a
little difficult to setup, but works quite well. Using it along with
shorewall and then some local detection software like tripwire (
http://www.tripwire.org/ ) makes for a good solution.

u can implement ur security by IPTABLES tool inbuilt in Linux. for more info just take a look at

http://geocities.com/alokchauhan1/IPMasqueradeHOWTO.pdf

This question was closed by the author