getting userspace iptables

hi,
I am confusing about how to get userspace iptables for linux kernel
version 2.4 and compiling that iptables. I want to add the following rule in the chain.

iptables -t mangle -A OUTPUT -o! "eth0" -m random --average 50 -j ACCEPT

But the random matching is not available in normal linux kernels. So I am in need of using userspace iptables.

can anybody help me to solve this problem?

Suresh Madhu D
Project Trainee
e-consystems
chennai