An IP Address is 4 sets of decimal numbers, 0-255, separated by periods (for example, 192.168.255.251) which form the address of a computer on the internet or within a local network, and allow it to be referenced by other computers.

An IP address consists of two parts, a network portion and a host portion.

Within a single network, for example the one you are about to set up, all computers will have identical network portions. In order for two computers to communicate with each other directly, they must be in the same network, and thus have identical network portions of their IP addresses.

The host portion of an IP address indicates a computer's unique identifier within its network. Every computer on a given network must have a unique host portion in order to communicate with other computers in the same network.

An IP address is always accompanied by a subnet mask, which separates the network and host portions of the IP address. A subnet mask is shown in the same format as the IP address (for example 255.255.255.0). As far as this article is concerned, assume that the values of the 4 sets of numbers in the subnet mask can be either 0 or 255.

Sets with the value of 0 indicate the host portion of the IP address, and sets with the value of 255 indicate the network portion. For example, with an IP address of 192.168.3.25 and a subnet mask of 255.255.255.0, the network portion of the address would be '192.168.3', and the host portion would be '.25'. This means the computer assigned this address is host 25 within the 192.168.3 network.

Things do get significantly more complex than this, especially when you consider that the subnet mask is not actually restricted only to values of 0 or 255, but that is beyond the scope of this article.

Now, on with the networking!