Reasonable filtering rules for Kernel-based Packet Screen
For a Kernel based packet screen, there are reasonably four filter rules which can be applied.
I am providing details of four, which are specifically written on Linux for ipfwadm.One is welcome to use these rules/principles on any others for packet screening on open source Unix systems .
The filer rules which can be applied are:
Please remember that, ipfwadm also has capabilities of masquerading (-M) . Please look on ipfwadm main page for further information on switches and options.
Check the link- http://l7-filter.sourceforge.net/HOWTO to understand further about rules which can be applied for kernel based packet screen. Also http://www.cs.binghamton.edu/~steflik/cs455/firewalls-faq.html and http://wiki.wireshark.org/Performance can be checked for further understanding as well.
I guess that should get you the things sorted out.