Native dual-stack is the top pick for most networks searching "v6": it runs IPv4 and IPv6 on the same links and hardware, so nothing is translated or tunneled. The criteria behind that pick are the four questions worth asking of any v6 option: does it deliver native IPv6 end to end, what breaks during the transition, what it costs in gear and staff time, and how you measure adoption once it is live.

v6

Native dual-stack

Every router, switch, and host gets both an IPv4 and an IPv6 address. Clients reach each service over whichever stack answers, and modern operating systems use Happy Eyeballs to avoid long stalls when one stack fails.

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• Pros: no translation layer, no stateful middlebox to size or debug, and IPv6-only services work for users on IPv6-capable access networks.
• Pros: address planning is straightforward once you follow the standard 128-bit addressing model from RFC 8200.
• Cons: your firewall, load balancer, monitoring, and access-control rules now exist twice, and drift between the two rule sets is the common failure mode.
• Cons: older customer premises gear, some VPN clients, and legacy appliances may not speak IPv6 at all.

Use it when you control both ends of the path and your equipment vendors ship current firmware.

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NAT64 with DNS64

NAT64 lets an IPv6-only host reach IPv4-only destinations by translating at the network edge, while DNS64 synthesizes AAAA records so clients ask for the name instead of the address. Mobile carriers use this pattern in IPv6-only cores, often paired with 464XLAT on the handset.

v3

• Pros: internal networks and client devices run one protocol, which cuts address management work and suits large fleets of mobile or IoT endpoints.
• Pros: keeps IPv4-only content reachable without giving every device a public IPv4 address.
• Cons: the translator needs a pool of IPv4 addresses and becomes a capacity and logging bottleneck.
• Cons: anything that embeds literal IPv4 addresses, including some peer-to-peer and legacy VoIP clients, can misbehave.

Use it when you own the client population and want to retire IPv4 inside the campus or carrier core.

Tunnels: 6in4, 6rd, and DS-Lite

Tunnels carry one protocol inside the other. 6in4 and 6rd put IPv6 inside IPv4 where native v6 is unavailable, and DS-Lite does the reverse, carrying IPv4 inside an IPv6 access network.

• Pros: quick path to v6 service on access networks that have not upgraded, and a way to keep legacy IPv4 service working over an IPv6-only last mile.
• Cons: extra encapsulation costs MTU headroom, and path MTU problems surface as odd failures on specific sites.
• Cons: tunnel brokers are a dependency you do not control, and throughput caps are common on free options.

Use tunnels as a bridge during a migration window, not as a permanent design.

Managed hosting, CDNs, and cloud load balancers

Most major hosting and CDN providers publish IPv6 endpoints for their front ends, which lets you ship v6 to the public without touching internal addressing. Check that origin connections, health checks, and logging include v6 addresses before you enable it.

• Pros: fast, reversible, and low staff cost.
• Cons: it does not make your internal network dual-stack, so a later migration still lands on your plate.

Use it when your v6 requirement is customer-facing reachability rather than internal addressing.

How to choose a v6 path

1. Inventory which access networks already deliver native IPv6 to your users.
2. Decide whether the goal is external reachability or internal addressing, since the two call for different designs.
3. Pick the option with the fewest translation points that still meets that goal.
4. Extend firewalls, monitoring, and inventory to v6 before you turn up service.
5. Track adoption with your own measurements rather than assuming traffic followed the address plan.

Scope note

This guide covers v6 as IPv6 in networking, the dominant use of the term. Other fields use "v6" for engine layouts and software release lines, which are unrelated to the options above.