Every machine on a network has a unique identifier. Just as you would address a letter to send in the mail, computers use the unique identifier to send data to specific computers on a network. Most networks today, including all computers on the Internet, use the TCP/IP protocol as the standard for how to communicate on the network. In the TCP/IP protocol, the unique identifier for a computer is called its IP address.

How does your computer get its IP address? An IP address can be either dynamic or static. A static address is one that you configure yourself by editing your computer's network settings. This type of address is rare and stable. Dynamic addresses are the most common, they are issued using a leasing system, meaning that the IP address is only active for a limited time.