"Mangesh V Rakhunde" linmangy@rediffmail.com writes:

I want to put a linux firewall between all LAN PCs and the router. In this setup I dont want to use valid IP as I am short of it. Can you give me some ideas to do it.

setup a ethernet-bridging firewall.. You'll have to use EBtables for that. check out ebtables.sf.net. Use a recent kernel for better features.. You just need a box running the Linux kernel, with two ethernet cards. You dont have to set up an IP number (private nor public) to any of the cards.