IPv6IPv4

IPv6IPv4 is a broad term used to describe the methods and configurations that enable IPv6 and IPv4 to operate together and interoperate on the same network infrastructure. It encompasses dual-stack deployments, IPv6-over-IPv4 and IPv4-over-IPv6 tunneling, and translation techniques that bridge IPv6 and IPv4 domains.

Dual-stack systems run both IPv4 and IPv6 protocols simultaneously, allowing native address assignment, DNS resolution, and application communication for both protocol families. Tunneling methods encapsulate IPv6 traffic inside an existing IPv4 path (for example, 6to4 or Teredo) or IPv4 traffic inside IPv6 packets to traverse networks that do not support native IPv6. Translation approaches, such as NAT64 paired with DNS64, enable IPv6 clients to communicate with IPv4 servers by translating addresses and protocols between the two worlds.

In addition, IPv4-embedded or mixed addressing schemes, such as IPv4-mapped IPv6 addresses, provide compatibility in some environments, though they have become less common as native dual-stack operation and translation techniques have matured. Implementations require coordination across routers, firewalls, DNS, and address planning. Transition technologies are subject to performance considerations and policy constraints, including potential impact on end-to-end security and the administrative overhead of maintaining two protocol stacks. As networks migrate toward IPv6, operators often combine dual-stack with selective deployment of translation or tunneling to maintain connectivity during transition.