from wireless ap to wired router/firewall

[zenlunatic]

I recently got cable. The modem is installed on the third floor of the house. We have a wireless router which allows me to connect my laptop, and we have an xp machine and a ps2 hooked wired to two of the four wired ports on the router.

I wanted to build my own router/firewall but the modem is in someone elses room and they don't want to have a machine sitting in there.

What I want to do is somehow build a box that is a router/firewall but connects to the internet using the wireless signal, so I can set up my own router in my room in the basement and connect a bunch of wired computers so I don't have to buy wireless cards for everything plus so I can have my own dedicated firewall. This is basically a standard gnu/linux or bsd dedicated router/firewall box, but which uses the wireless to get to the internet instead of a second network card. Can this be done?

I looked into these wireless bridge things but I was wondering if I could do something like I've described with a bsd or gnu/linux box with wireless card and a network card which is plugged into a switch like a normal bsd or gnu/linux router.

I know this isn't the most ideal setup for a home network, but its all I got for now. At least my part of the network will be firewalled off from the windows side. Thanks.

[fordp]

The good news: Should be no Problem.
The bad news: It's a tad complicated.

To make sure I understood your setup:

Internet-----M----WR--|WN|--R--|YN|

Where M denotes Modem, WR wireless router, WN wireless net, R your router, YN your net.
If this is correct, here is what you want to do:

The WN has a certain address space, probably something like 192.168.*.* or 10.47.0.* .
For YN you choose a different one, i.e. if WN is 192.168.0.*, 192.168.1.* would be a decent choice for YN.

Finally you must configure your kernel to pass all traffic coming from YN on to the WR,
which is done by an appropriate configuration of your iptables or ipchains (depends on the kernel you use).