IP6

IP6 stands for Internet Protocol version 6, the successor to IPv4, designed by the Internet Engineering Task Force (IETF) to address address exhaustion and to enable improved routing and new features. IPv6 provides a 128-bit address space, allowing a vastly larger number of unique addresses, along with options for more efficient header processing, autoconfiguration, and enhanced multicast and mobility support. The standard is defined in a series of IETF documents and related RFCs.

Addresses in IPv6 are written as eight groups of four hexadecimal digits separated by colons, with rules for zero compression and optional brackets for literals in URLs. Global unicast addresses are routable on the Internet, while link-local and unique local addresses serve local or private contexts. The loopback address is ::1 and the unspecified address is ::.

IPv6 uses a fixed-length header of 40 bytes and employs extension headers for optional information, enabling features such as traffic class, flow labels, and secure delivery. It supports stateless address autoconfiguration (SLAAC), allowing devices to generate their own addresses based on network prefixes, typically with optional stateful configuration through DHCPv6. Security considerations include IPsec, originally envisioned as mandatory, though implementation remains optional.

Deployment of IPv6 is not backward compatible with IPv4, so dual-stack configurations and transition mechanisms are used to facilitate coexistence. Transition methods include tunneling protocols such as 6to4 and Teredo, and translation strategies like NAT64 with DNS64. Global adoption has grown, with most major networks and operating systems supporting IPv6, though IPv4 remains in widespread use.

In summary, IPv6 provides a vastly larger address space, simplified and scalable routing, and modern autoconfiguration and mobility support, while continuing to coexist with IPv4 through a variety of transition techniques.