What is IP address?

192.168.1.101

Internet Protocol Address, or IP address is a number used to indicate the location of a computer or other device on a network using TCP/IP. These addresses allow data to reach the appropriate destination on a network and the Internet.

That is to say it is designed to allow one computer (or other digital device) to communicate with another via the Internet. It also allows the location of literally billions of digital devices that are connected to the Internet to be pinpointed and differentiated from other devices.

For example, if someone needs your mailing address to send you a letter, a remote computer needs your IP address to communicate with your computer.

IPv4 addresses

An IP address consists of four numeric numbers (e.g. XXX.XXX.XXX), each number contains one to three digits, with a single dot (.) separating each number. Each of the four numbers can range from 0 to 255. An example of what an IP address might look like: 192.168.1.101. This group of numbers is the key to sending and retrieving data over Internet connections, ensuring that requests for data and the data requested, will reach their correct Internet destinations. Without this numeric protocol, sending and receiving data over the Internet would not be possible.

What is an IP Class?

With an IPv4 IP address, there are five classes of available IP ranges: Class A, Class B, Class C, Class D and Class E. Only Classes A, B, and C are commonly used. Each class allows for a range of valid IP addresses, shown in the following table.

Ranges 127.x.x.x are reserved for the loopback or localhost, for example, 127.0.0.1 is the loopback address. Range 255.255.255.255 broadcasts to all hosts on the local network.

For more information please read the following articles:

http://www.computerhope.com/jargon/i/ip.htm