IPAdresse

An IP address is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. It serves two main functions: identifying the host and providing a location for routing data packets.

IPv4, the first widely deployed version, uses 32-bit addresses written as four decimal octets separated by dots, for example 192.0.2.1. The finite space is 0.0.0.0 to 255.255.255.255, with several ranges reserved for special use. Private address spaces such as 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 are commonly used within local networks.

IPv6, designed to replace IPv4, uses 128-bit addresses written in hexadecimal and separated by colons, for example 2001:0db8:85a3:0000:0000:8a2e:0370:7334, often abbreviated. It provides a vastly larger address space and includes features such as automatic address configuration (SLAAC), built-in multicast, and improved header efficiency. Public IPv6 addresses are routable on the Internet, while link-local addresses are used for local network communication.

Addresses may be assigned dynamically by a DHCP server or configured statically. In many networks, a public IP is assigned to the gateway router, and multiple devices share it through network address translation (NAT). Subnetting, defined by a network prefix length (for IPv4) or CIDR notation, determines how a single address space is divided into networks and influences routing.

IP address handling raises privacy and security considerations, as addresses can reveal approximate location and activity. Management tasks include allocation, auditing, and the use of firewalls and access controls to regulate traffic. The transition from IPv4 to IPv6 has been gradual, with dual-stack deployment and tunneling mechanisms to maintain compatibility.