YH's Blog

Requirements:
a computer with at least 2 network adapters . - refered as "Server" or "Gateway PC"; the adapter which connects to the cable Modem is referred as inet1, the adapter connecting to the ADSL Modem is referred as priv1.
an ADSL broadband router. (hahaha of course)
a cable Modem.
any other PC which want to access the outside network. - refered as "Client PCs";

Steps under Windows XP
connect all the cables.
1. Setup the Server as usual. Use the automatic setting for the inet1. Enable the Internet Sharing.
2. Manually set the priv1 IP and default network mask, leave the default gateway empty. Use the DNS setting of the inet1 for the priv1 DNS setting.
3. on a client PC. set the IP address in the same network and network mask. Use the Server priv1 IP address as its default gateway. Also use the priv1 DNS as its DNS setting.

something need to be mentioned here. If you run a firewall software on the Server, you may need to change it to the a Default Gateway setting(in my case).

Everything's done now.

cons and pros:
cons:
1. you need a server running constantly to provide the Internet sharing services for the rest of client PCs.
2. the ADSL router functionalities are not fully used. the router is mainly used as a switch with wireless accessibility ( in my case).
3. Settings are a bit complicated.

pros:
1. you get higher level of security. Unless the new plugging-in client PC knows the setting for the network adapter, it won't be able to access the Internet at all.
2. No need to throw away your lovely, perfectly working ADSL router.
3. You've learned more.