IP addresses basically specify a specific computer or node (the host) within a larger set of nodes (or the network). The use of the subnet mask is to determine the IP addresses for the network and host seperately. So a subnet mask basically takes an IP address and splits it into a host part and a network part.
Subnet masks are not IP addresses, they simply work along with them to help in the splitting. eg. If your IP address is 192.168.1.10 and your subnet mask is 255.255.255.0 192.168.1.10 = 11000000.10101000.00000001.00001010 255.255.255.0 = 11111111.11111111.11111111.00000000 If you AND the two together, you'll get the network address : 192.168.1.X which means the network has IP's in the range 192.168.1.0 - 192.168.1.255 The host portion is basically the remaining part. ie. 10. So you are host number 10 in the network 192.168.1.X It's not generally this simple and there are many small complications but that's the gist of it that I understand! [Non-text portions of this message have been removed]
