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What is Dual Stack Networking?

Dual stack networking is a setup where a network or device runs both IPv4 and IPv6 at the same time. One system can communicate using either protocol, depending on what’s needed.

How does dual stack networking work? When your device wants to connect to a website, it performs a DNS lookup. If it gets an IPv4 address (A record), it uses IPv4. If it gets an IPv6 address (AAAA record), it uses IPv6. If both are available, the system chooses the best option automatically.

Why does dual stack networking exist? The internet is in a transition phase. There’s a limited number of IPv4 addresses, with not enough to assign to all the internet-connected devices we use in modern life. The new system, IPv6, has a massive amount of available addresses. However, we can’t switch from IPv4 to IPv6 all at once, so both must coexist for a while. IPv4 addresses officially ran out globally in 2011, and IPv6 addresses were launched in 2012.

Dual stack doesn’t “merge” IPv4 and IPv6, it runs them in parallel. Devices still use one protocol per connection, not both at once.

You can use an IP address tool to see what your IPv4 and IPv6 addresses are.