What is an IP address?
IP addresses are unique codes that identify any given device on the Internet or on a local network. They provide a method of communication between different systems that are connected using the internet protocol. There are two primary types of IP address formats used today — IPv4 and IPv6.
IPv4
A standard IPv4 address consist of four sets of numbers, separated by three dots, from 0 to 255. For instance, the IP address of facebook.com is 31.13.70.36. This number is used to recognize the Facebook website on the Internet. When you visit “http://facebook.com” in your web browser, the domain name "facebook.com" is automatically interpreted to the IP address "31.13.70.36" by the DNS system.
IPv4 addresses have three classes of sets that can be registered through the InterNIC. The largest block is Class A, which contains 16,777,216 IP addresses (e.g. 123.xxx.xxx.xxx), after which comes Class B, which contains 65,536 IP addresses (e.g. 123.123.xxx.xxx). The smallest is Class C, which consists of 256 IP addresses (e.g. 123.123.123.xxx — where xxx is 0 to 255).
The total number of IPv4 addresses is ranged between 000.000.000.000 to 255.255.255.255 because 256 = 28, hence there are (28)4 (or 4,294,967,296) possible IP addresses. This may seem like a large number, but it is no longer enough to cover all the devices connected to the Internet worldwide. Therefore, many devices now use IPv6 addresses.
IPv6
The IPv6 address format is much different than the IPv4 format. It uses colons to separate each block and contains eight sets of four hexadecimal digits. An example of an IPv6 address is: 2602:0445:0000:0000:a93e:5ca7:81e2:5f9d. There are 3.4 x 1038 (or 340 undecillionths) possible IPv6 addresses, meaning we shouldn't run out of IPv6 addresses anytime soon.