IPv4, or Internet Protocol version 4, is a protocol used for communicating data over the internet. It is the fourth version of the Internet Protocol and has been in use since the early days of the internet.
IPv4 addresses are 32-bit numbers, expressed in four octets, separated by dots. Each octet can range from 0 to 255, which gives a total of 4,294,967,296 unique IPv4 addresses. However, not all of these addresses are available for use, as some of them are reserved for specific purposes, such as private networks, multicast, and broadcast.
IPv4 is a connectionless protocol, which means that it does not establish a dedicated connection between the sender and the receiver before transmitting data. Instead, each packet of data contains the source and destination IP addresses, as well as other information needed for routing and error checking.
One of the main issues with IPv4 is the limited number of available addresses. With the rapid growth of the internet and the increasing number of devices connected to it, the pool of available IPv4 addresses has been depleted over time. To address this issue, a new version of the protocol, IPv6, was introduced. IPv6 uses 128-bit addresses, which allow for a virtually unlimited number of unique addresses.
Despite the introduction of IPv6, IPv4 is still widely used today. Many devices, applications, and networks continue to rely on IPv4, and the transition to IPv6 is ongoing but slow. To address the issue of address exhaustion, various techniques have been developed to enable multiple devices to share a single IPv4 address, such as Network Address Translation (NAT).
In summary, IPv4 is the fourth version of the Internet Protocol and is used for transmitting data over the internet. It uses 32-bit addresses and is a connectionless protocol. Although it has limitations due to its limited number of available addresses, it is still widely used today, and the transition to IPv6 is ongoing.