http://www.yolinux.com/TUTORIALS/LinuxTutorialNetworking.html#CONFIGFILES
http://www.yolinux.com/TUTORIALS/LinuxTutorialIptablesNetworkGateway.html
192.168.0.0 – 192.168.255.255
netmask: 255.255.255.0
ex: 192.168.12.168
172.16.0.0 – 172.31.255.255
netmask: 255.255.0.0
ex:172.16.2.x (x = 1 – 254)
10.0.0.0 – 10.255.255.255
netmask: 255.0.0.0