About the ipconfig - XP

what is the 255.255.255.0 and 192.168.0.1 ?
and why are they like that in all computers ? why it is not 145.167.133.0 or 132.144.133.0 in place of 255.255.255.0 ??

thanx

255.255.255.0 is a class C subnet mask, while 192.168.0.1 is an ip address for an internal network that is usually used as the gateway address on the router. All of the devices on that network would be from 192.168.0.2 to 192.168.0.254 (192.168.0.255 is a broadcast address for sending to all devices on the network), so you can have 254 pc, printer, or other devices on such a network. The other "different" address that you may see will be your Internet provider address assigned to you either static or dynamically.