dualstacked

Dualstacked refers to devices, networks, or configurations that support both Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6) simultaneously. In such setups, a host or path can carry traffic for both protocol suites, exposing IPv4 and IPv6 addresses and services. The term is commonly used to describe dual-stack networks, whose aim is to preserve compatibility with existing IPv4 infrastructure while enabling native IPv6 connectivity.

Implementation typically involves running two parallel protocol stacks on endpoints, routers, and servers. DNS must provide both A and AAAA records, and address assignment may use DHCPv4 for IPv4 and DHCPv6 or Stateless Address Autoconfiguration (SLAAC) for IPv6. Routers maintain separate routing information for each protocol, and transition mechanisms such as NAT64 with DNS64 may be used at the network edge to enable IPv6-only clients to reach IPv4 servers.

Benefits include smoother transition from IPv4 to IPv6, continued access to IPv4 hosts, and flexibility for gradual deployment. Dual-stacked networks can support new IPv6 features while remaining compatible with existing IPv4 services, reducing the need for disruptive rewrites of applications or infrastructure.

Challenges encompass increased configuration and operational complexity, security policy management for two protocol stacks, and potential performance and troubleshooting overhead. Some devices or applications may misbehave when both protocols are enabled, and IPv6 address management requires new practices and monitoring.

Terminology and related concepts: "dualstacked" is an adjective form of "dual-stack." It is distinct from DS-Lite (Dual-Stack Lite), a transition technique that carries IPv4 traffic over an IPv6 network. The dual-stack approach is widely deployed in enterprise and service-provider networks as part of IPv6 adoption strategies.