EndoShield is another great script I've used (in fact I got it going just the other night again. With very little cusomtization it'll run quite well.

I think you can get it from sourceforge.net.

ipchains
 

Thanks, for your help, I will try it!
Don't you happen to know what that word 'dns' mean be in the sample command? It seems that my system dislikes it.

If you have a dynamic IP address, there is no reason to run DNS yourself, and in fact you will likely run into problems doing reverse lookups. Why don't you just shut your dns server (local) off, and specify your ISP's dns. Then you can take those references to 'dns' out of your ipchains script.