FernTool

What is IPv6?

IPv6 (Internet Protocol version 6) is the newer version of the addressing system that every device on the internet uses to find every other device. It replaces IPv4, which has been in use since 1983 and has effectively run out of addresses. If you want to know whether your connection already uses it, run the FernTool IPv6 test — it takes a second.

Why IPv6 exists

An IPv4 address is 32 bits long, which allows about 4.3 billion unique addresses. That sounded enormous in the 1980s, but today there are more phones on the planet than people, plus laptops, TVs, cameras and servers. The regional internet registries handed out their last free IPv4 blocks in the 2010s (AFRINIC, which serves Africa, was the last to reach exhaustion). New networks now have to buy IPv4 space second-hand or share it.

IPv6 addresses are 128 bits long. That gives roughly 3.4 × 1038 addresses — enough to give every device its own globally unique address for the foreseeable future, without tricks like carrier-grade NAT.

What an IPv6 address looks like

IPv4 is written as four decimal numbers separated by dots, such as 196.25.1.1. IPv6 is written as eight groups of four hexadecimal digits separated by colons:

2001:0db8:0000:0000:0000:ff00:0042:8329

Two shortcuts keep it readable. Leading zeros in a group can be dropped (0db8 → db8), and one run of all-zero groups can be replaced by a double colon. So the address above becomes 2001:db8::ff00:42:8329. You can paste any address into the IP lookup tool to validate it and see its expanded form.

The parts of an IPv6 address

The first 64 bits are usually the network prefix, assigned by your ISP (your home typically gets a /56 or /64 block). The last 64 bits are the interface identifier, which your device picks itself. Modern operating systems generate random, regularly changing interface identifiers (“privacy extensions”) so that your device can’t be tracked across networks by its address.

Special IPv6 ranges

IPv6 vs IPv4: the key differences

Address size
32 bits vs 128 bits
Notation
Dotted decimal vs colon hex
NAT
Needed on IPv4; not needed on IPv6
Configuration
DHCP vs SLAAC or DHCPv6
Header
Variable vs simpler fixed header
Broadcast
Yes vs none (multicast instead)

The biggest practical difference is end-to-end reachability. On IPv4, your router translates one public address for all the devices in your home (NAT), and mobile networks often share one address among hundreds of customers. On IPv6, each device can have its own public address. That makes things like gaming, video calls and peer-to-peer apps simpler, but it also means your router’s firewall — not NAT — is what keeps unwanted traffic out. Every mainstream router blocks unsolicited inbound IPv6 by default.

Is IPv6 faster?

Not inherently. Speed depends on the route your traffic takes. In practice IPv6 can be slightly faster on networks where IPv4 traffic has to pass through large CGNAT systems, and slightly slower where an ISP’s IPv6 routing is less mature. Browsers use a technique called “Happy Eyeballs” to try both and pick whichever answers first, so you shouldn’t notice a difference.

Do I have IPv6?

The quickest check is the IPv6 test. Your public IP on the homepage will also be shown in IPv6 format (with colons) if your browser connected over IPv6. If you only see an IPv4 address, one of these is usually the reason:

  1. Your ISP doesn’t offer IPv6 on your product yet.
  2. Your router supports IPv6 but it is switched off — look for an “IPv6” or “WAN IPv6” setting and choose automatic/DHCPv6-PD.
  3. A VPN is tunnelling only IPv4 and blocking IPv6 (good VPNs do this to prevent leaks — see the VPN leak test).

In South Africa, several ISPs announce IPv6 networks, including Telkom, Afrihost, Rain and Cool Ideas — see our South African ISP guides.

Should I turn IPv6 off?

Generally no. Microsoft, Apple and Google all recommend leaving it enabled; parts of Windows expect it. The one situation where disabling IPv6 helps is with an old VPN that doesn’t handle IPv6 and leaks your real address over it. The better fix there is a VPN that supports or blocks IPv6 properly.

Will IPv4 disappear?

Not soon. The two protocols run side by side (“dual stack”), and most websites are reachable over both. Google’s public statistics show that a large and steadily growing share of its users now reach it over IPv6, varying widely by country and ISP. Expect dual-stack to be the norm for years.

Frequently asked questions

What is IPv6 in simple terms?

IPv6 is the newer internet addressing system. It uses 128-bit addresses written in hexadecimal with colons, giving practically unlimited addresses, whereas IPv4 has only about 4.3 billion.

Is IPv6 better than IPv4?

IPv6 is better for scale and end-to-end connectivity because it removes the need for NAT. Speed and security are similar; your router firewall protects IPv6 devices.

How do I know if I have IPv6?

Open the FernTool IPv6 test. If it shows an address containing colons, your connection supports IPv6.

Should I disable IPv6?

Usually not. Only consider it if an old VPN leaks your real IP over IPv6; a modern VPN is the better fix.

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