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NAT64

NAT64 enables translation between IPv4 and IPv6, allowing networks to run both protocols simultaneously during the transition away from IPv4. It bridges legacy IPv4 segments with modern IPv6 infrastructure without disrupting network operations.

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About this video

Most modern networks still depend on IPv4 for a significant portion of their infrastructure, applications, and services, even as IPv6 adoption continues to grow. A hard cutover from one protocol to the other is rarely feasible, which is why transition mechanisms like NAT64 exist to bridge the gap and keep networks functioning throughout the migration process. NAT64 translates traffic between IPv4 and IPv6 in both directions, allowing IPv4-only and IPv6-only segments of a network to communicate with each other seamlessly. This makes it possible to modernize parts of a network incrementally without forcing all devices and systems to support both protocols at the same time. It is worth distinguishing NAT64 from the kind of address translation that IPv6 was designed to make obsolete. IPv6 was built with an enormous address space specifically so that private-to-public NAT would no longer be necessary. Every device intended to communicate on the internet can be assigned a globally unique IPv6 address directly, eliminating the need to translate internal addresses outward. Unique local addresses exist within IPv6 for internal communication, similar to private IPv4 ranges, but these are never intended to be translated to global addresses. NAT64 is not about that kind of translation — its purpose is strictly to enable interoperability between the two protocol generations as networks move away from IPv4 and toward a fully IPv6 environment.

What you'll learn

What's covered

NAT64 and IPv4 to IPv6 Transition

Aligned to

Cisco CCNA
1.9 Describe IPv6 address types
4.1 Configure and verify inside source NAT using static and pools
1.8 Configure and verify IPv6 addressing and prefix
1.7 Describe private IPv4 addressing

Key terms

Network Address Translation
NAT
A method that maps private IP addresses to a public IP address, allowing multiple devices to share a single public IP.
NAT64
A transition mechanism that translates between IPv4 and IPv6 addresses, enabling communication between IPv4-only and IPv6-only network segments.
IPv4
The fourth version of the Internet Protocol, using 32-bit addresses that provide approximately 4.3 billion unique addresses.
IPv6
The sixth version of the Internet Protocol, using 128-bit addresses written in hexadecimal and separated by colons to provide a vastly larger address space than IPv4's 32-bit addresses. IPv6 also introduces built-in features like SLAAC, NDP, and mandatory support for IPsec.
Unique Local Address
An IPv6 address in the FC00::/7 range (most commonly FD00::/8) used for private internal network communication, analogous to IPv4 private address ranges like 192.168.0.0/16. Unique local addresses are not routable on the public internet but can be routed within an organization's own network.
Global Unicast Address
GUA
A publicly routable IPv6 unicast address beginning with the prefix 2000::/3, equivalent in role to a public IPv4 address, used to identify a device uniquely across the internet. GUAs are assigned by ISPs and regional internet registries and are the addresses used for internet-facing communication in IPv6.

Transcript

We still heavily rely on IPv4. A lot of our networks, a lot of our applications, and a lot of what we have rely on the use of IPv4, but we really need to make the switch to IPv6. So how do we straddle between IPv4 and IPv6, and how do we make a transition, a smooth transition, without just stopping our networks from operating correctly? One of the answers is NAT64.

IPv6 shouldn't need address translation

The first thing that I want to stress is that IPv6 really shouldn't need network address translation, at least not from the standpoint of converting an IPv6 local address to an IPv6 global address. IPv6 was created from the ground up, and one of the things that was established was a huge address space, so that we wouldn't need private addresses in the future.

I guess that's a little untrue, because we do have these unique local addresses. The unique local address acts similar to a private address of the IPv4 range. That is, it is local to the company, so it should exist so that within the company communication can happen back and forth. But that's never meant to be translated to the outside world. What goes to the outside world is these global unique addresses. Every machine on your network that wants to communicate to the internet, wants to communicate globally, should get this assigned to it directly, or should create it directly on that machine. So the unique local address is unique to that, but never gets translated to a global unique address. There should never be an IPv6 to IPv6 network address translation for the purpose of communicating with the rest of the world.

What NAT64 does

So what is NAT64? NAT64 allows us to translate from IPv4 to IPv6 and back again. That way, we can have segments of our network that operate as IPv4 for facilitating older technologies, and then areas of the network that operate at IPv6. So it helps in the translation as we move from an old setup of IPv4 to IPv6.

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