Networks are set up to allow for a number of hosts in a given subnet. These hosts are given one Internet Protocol (IP) address from a range of addresses that are defined by a subnet mask. The subnet mask essentially tells the router what range of IP addresses the router is allowed to assign for the given subnet. You can find the range of IP addresses for your subnet by looking at the subnet mask.
Launch a command prompt or terminal window, depending on your operating system's terminology. In Microsoft Windows you can do this by simultaneously pressing the meta, or Windows, key and the "R" key on your keyboard. On most other operating systems, simply double-click the Terminal application shortcut.
Type "ipconfig" if you are using Microsoft Windows or "ifconfig" if you are using a UNIX-like operating system such as Apple's Mac OS X, BSD, or Linux. Write down your IP Address, sometimes called the "inet addr," and your mask.
Find your IP range by examining your subnet mask. Most likely, if you are using a simple home network, your IP address begins with 192.168.0 and your mask is 255.255.255.0. This mask means that the address range 192.168.0.1 to 192.168.0.255 is available for assignment in your subnet.