NAT64

Summary

This video explains NAT64, a transition mechanism enabling IPv6-only hosts to communicate with IPv4-only servers. NAT64 translates IPv6 addresses to IPv4 for seamless communication, utilizing a slash 96 prefix. It works by mapping the IPv6 prefix to an IPv4 address through a NAT64 router, which then forwards the packet after converting the header. The video also introduces DNS64, which helps resolve DNS queries for IPv6-only clients. NAT64 is especially useful for mobile providers facing IPv4 address shortages, though it requires IPv6-compatible devices and apps. The video highlights the potential and limitations of these transition mechanisms.

Takeaways

• 😀 NAT64 enables communication between IPv6-only hosts and IPv4-only servers.
• 😀 NAT64 is based on the existing NAT mechanism used for IPv4 communication.
• 😀 With NAT64, IPv6-only customers are connected to the ISP's IPv4 infrastructure via a NAT64 router.
• 😀 NAT64 allows the translation of IPv6 addresses into IPv4 addresses, making communication possible despite the absence of IPv4 connectivity.
• 😀 For NAT64, a /96 prefix is required to map IPv4 addresses into IPv6 addresses, since IPv6 addresses are 128 bits and IPv4 addresses are 32 bits.
• 😀 A well-known prefix reserved for NAT64 can be used, but it should never be announced to the internet and is meant for local access.
• 😀 Once the IPv6 address is mapped to IPv4 via NAT64, the NAT64 router strips off the IPv6 header and adds an IPv4 header before forwarding the packet.
• 😀 NAT64 can be implemented either statelessly (stateless NAT64) or with stateful mapping (stateful NAT64).
• 😀 DNS64 is used to resolve issues when an IPv6-only client queries an IPv4-only website, by mapping IPv4 addresses to IPv6 addresses based on the NAT64 prefix.
• 😀 NAT64 is particularly useful for mobile providers due to the increasing number of devices and the shortage of available IPv4 addresses.
• 😀 For NAT64 to work, mobile phones and devices need to support IPv6, but not all apps currently support IPv6.

Q & A

What is the purpose of NAT 64?

NAT 64 enables communication between IPv6-only hosts and IPv4-only servers, facilitating a transition mechanism where IPv6 devices can interact with IPv4 networks.

How does NAT 64 differ from traditional NAT used for IPv4?

While traditional NAT is used for translating private IPv4 addresses to public IPv4 addresses, NAT 64 maps an IPv6 prefix into an IPv4 address, allowing IPv6-only hosts to access IPv4 networks.

Why is NAT 64 important for customers with IPv6-only connectivity?

It allows IPv6-only customers to access IPv4 services, providing a necessary bridge in environments where IPv4 infrastructure still exists but the customer only has IPv6 connectivity.

What is the role of the NAT 64 router?

The NAT 64 router is responsible for mapping the IPv6 prefix to an IPv4 address, stripping the IPv6 header, and replacing it with an IPv4 header before forwarding the packet to the destination.

How is the IPv6 address constructed for NAT 64?

The IPv6 address for NAT 64 is constructed using a 96-bit prefix that maps the 32-bit IPv4 address into the 128-bit IPv6 address, leaving 96 bits for the mapping.

What is the difference between stateless and stateful NAT 64?

In stateless NAT 64, the mapping is predefined and does not rely on session tracking, while in stateful NAT 64, the mapping is dynamic and relies on maintaining the state of the session.

How does DNS-64 work in conjunction with NAT 64?

DNS-64 helps IPv6 clients access IPv4-only websites by mapping the A record (IPv4 address) into a Quad-A record (IPv6 address) based on the NAT 64 router's IPv6 prefix.

What happens if an IPv6-only client requests a Quad-A record and the DNS response is empty?

In this case, the DNS-64 server will create a Quad-A record by mapping the A record from the IPv4 address, allowing the IPv6 client to still access the IPv4 site.

Why is NAT 64 particularly useful for mobile providers?

NAT 64 is beneficial for mobile providers because it addresses the shortage of IPv4 addresses while enabling massive numbers of devices to connect using IPv6-only, which is more scalable.

What challenges might mobile phone users face with NAT 64?

Mobile phones need to support IPv6 for NAT 64 to work. However, not all mobile apps currently support IPv6, which can cause compatibility issues in some cases.