IPv4 vs IPv6: what's the difference?

IPv4 and IPv6 are two versions of the Internet Protocol. They do the same job, but IPv6 has vastly more addresses because the world ran out of IPv4 ones.

At a glance

Why IPv4 ran out

IPv4 was designed in the early 1980s, when 4.3 billion addresses seemed like plenty. Then came home broadband, smartphones, and billions of connected devices. In February 2011 IANA handed out its last free blocks to the regional registries. APNIC, which serves Australia and the Asia-Pacific, reached its final block two months later, the first region to do so.

Since then, providers have stretched IPv4 by sharing addresses. Your home router shares one public address across all your devices, and many providers use carrier-grade NAT (CGNAT) to share one address across many customers. It works, but it adds complexity and can break things like gaming, remote access and hosting from home.

How IPv6 addresses are written

An IPv6 address is eight groups of four hexadecimal digits (0–9 and a–f), separated by colons:

That's long, so two shortcuts are allowed:

• Leading zeros in a group can be dropped: 0db8 becomes db8.
• One run of all-zero groups can be replaced by a double colon: :0000:0000:0000: becomes ::.

So the address above is usually written as:

Why you might have both

IPv4 and IPv6 can't talk to each other directly, so the internet runs both side by side during a long transition. If your provider supports IPv6, your connection is probably "dual-stack": it has an IPv4 address and an IPv6 address. Your device uses IPv6 when a website supports it and falls back to IPv4 when it doesn't. That's why our checker shows two separate results.

Does my connection support IPv6?

The quickest way to find out is to check your IP address. If an IPv6 address appears, your connection supports it.

If it shows "Not detected", common reasons are:

• Your internet provider doesn't offer IPv6 yet, or hasn't enabled it on your plan.
• Your router doesn't support IPv6 or has it switched off. Look for an IPv6 setting in its admin page.
• A VPN or security software is blocking IPv6. Some VPNs disable it to stop address leaks.

Support in Australia varies by provider, and many mobile networks now use IPv6 by default. If you want it on your home connection, ask your provider whether it's available on your plan.

Is IPv6 better?

For everyday browsing you won't notice a difference. Neither is meaningfully faster. IPv6's advantages are mostly behind the scenes: no address shortage, less need for address sharing, simpler routing, and easier direct connections between devices. Over time, as more of the internet supports it, IPv6 will become the main protocol and IPv4 the fallback.