If I'm understanding your question correctly, you're asking what part of an IP address is used for the clients on a network? If this is so, then the answer is false. An IP address has two parts, the network bits, and host bits. The network bits are reserved for defining the network subnet mask, while the host bits are reserved for the clients on that network. So for instance if I have a class C subnet of 255.255.255.0, that would mean that the 255.255.255 is my network portion of the subnet, while the .0 is the host portion of my subnet. This would mean that I could have up to 255 hosts on the network (192.168.1.0 through 192.168.1.254).
