How To Test Your Linux Server's Firewall with the Free Tool FTester

[mandy]

Step-by-step guide to testing your Linux server's firewall with the free tool FTester

What is FTester ?
The Firewall Tester (FTester) is a tool designed for testing firewalls filtering policies and Intrusion Detection System (IDS) capabilities.

The tool consists of two perl scripts, a packet injector (ftest) and the listening sniffer (ftestd).
The first script injects custom packets, defined in ftest.conf, with a signature in the data part while the sniffer listens for such marked packets.

The scripts both write a log file which is in the same form for both scripts.

A diff of the two produced files (ftest.log and ftestd.log) shows the packets that were unable to reach the sniffer due to filtering rules if these two scripts are ran on hosts placed on two different sides of a firewall.

Stateful inspection firewalls are handled with the 'connection spoofing' option.

A script called freport is also available for automatically parse the log files...

full tutorial: http://www.howtoforge.com/test_your_linu...th_ftester