[ILUG] Kernel 2.4 replacement for ipchains

[Ruairi Newman]

Hi all,

I'm currently running Mandrake 7.2, recently updated to kernel
2.4.0-ac9.   Since I updated the kernel (the kernel shipped w/Mandake
7.2 is 2.2.17), ipchains have ceased to function at all.

While I know there is a replacement for ipchains in the 2.4 kernel in
the form of network packet filtering, I can find no information on it
that enables me to use it to secure the open ports on my system, as I
could with ipchains.

Can anybody point me in the right direction (HOWTO, general info)?  I
have already trawled through the documentation in the kernel source
tree, and found nothing that didn't assume that the reader is a C
programmer.

Thanks,

Ruairi