The scenario is
1) you are a home user
2) you have broad band connection from your ISP (Say BSNL,Tata,Airtel etc etc)
3)you have multiple computers at home
You want to share your internet connection among many users at home.
On one of the computers you need to install a software known as CCProxy and on rest of the machines you need to give IP address of this computer where CC proxy is installed.
The machine where CCproxy is installed will be gateway for rest of the computers and CCproxy needs to be installed only on one computer not on all.
I have done same on Ubuntu machines with squid in case you want to dive in your hands to Linux based proxy servers you can use squid as a proxy.
Apache can also be used as proxy (different from Apache Reverse proxy) but if not configured properly you might be used as an open proxy which is very dangerous.
It is much simpler than developing drivers etc
Hope you enjoyed this non geeky stuff :)