5.1 Selecting a Kernel

To create a filtering firewall, you don't need any special software. Linux will do. At the time of this writing I'm using RedHat 6.1.

The bilt in Linux firewall have changed several times. If you are using an old Linux kernel (1.0.x or older) geta new copy. These older used ipfwadm from http://www.xos.nl/linux/ipfwadm/ and is no longer supported.

If you are using 2.2.13 or newer you will be using ipchaining as developed by http://www.rustcorp.com/linux/ipchains/

If you are using the newer 2.4 kernal there is a new firewall utility with more feachers. I will write about this soon.