Makeing A Firewall

I am making a firewall box out of an old 900 mhz box .. is there some were that I can get more information on how to write a yast kernal just for fire wall so it is the only thing running on that box? Along with that I am looking for the configuration information - allowed sites disallowed and prots to open and shut. thanks

I am making a firewall box out of an old 900 mhz box .. is there some were that I can get more information on how to write a yast kernal just for fire wall so it is the only thing running on that box? Along with that I am looking for the configuration information - allowed sites disallowed and prots to open and shut. thanks
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IPCop Linux based firewall

m0n0wall barebones Free BSD based firewall

Paul