MyIPInfo

If you’ve ever looked at your IP address, you’ve probably noticed two very different formats. The shorter one like 203.0.113.45 is IPv4. The much longer one like 2001:db8:85a3::8a2e:370:7334 is IPv6. They are not replacements for each other — they are two parallel address systems that the modern internet uses at the same time.

The Short History

The internet was originally designed with IPv4, which uses 32 bits per address. That gives roughly 4.3 billion possible addresses, which seemed like an absurd amount in 1980 when computers were rare and expensive.

By the mid-2010s, we ran out. Every smartphone, laptop, smart fridge, and cloud server competes for those 4.3 billion slots. The world has been kept running with tricks like NAT (sharing one public IP across many devices) and ever-tighter address reuse, but the long-term answer is more address space.

That’s IPv6, which uses 128 bits — enough for 340 undecillion addresses (3.4 × 10³⁸). For practical purposes, it’s effectively infinite. Every grain of sand on Earth could have trillions of IPv6 addresses to itself.

What the Addresses Look Like

IPv4 uses four numbers (0-255) separated by dots:

  • 203.0.113.45 — a “normal” public IP
  • 192.168.1.1 — your typical home router’s private IP
  • 10.0.0.1, 172.16.x.x — private ranges used inside corporate networks

IPv6 uses eight groups of 4 hexadecimal characters separated by colons:

  • 2001:0db8:85a3:0000:0000:8a2e:0370:7334 — full form
  • 2001:db8:85a3::8a2e:370:7334 — shortened (leading zeros and one run of zero groups can be compressed to ::)
  • fe80::1 — a “link-local” address that only works on your local network

The shortening rules feel arbitrary at first but become natural after you’ve seen a few addresses. The :: shortcut can only appear once per address — otherwise you couldn’t tell how many groups it stands for.

Why You Probably Use Both Already

Most modern ISPs and mobile networks provide “dual stack” — both IPv4 and IPv6 work simultaneously. Your phone, laptop, and router all have addresses on both. When you visit a website, your device picks whichever address family the destination supports, with a slight preference for IPv6 if both work.

You can verify this on MyIPInfo: if your network is dual-stack, the site will show separate IPv4 and IPv6 addresses for the same device.

Practical Differences for Users

For everyday browsing, the experience is identical. You won’t notice which protocol is being used. But a few practical things change:

  • NAT vs unique addresses: Behind IPv4 NAT, every device in your home shares one public IP. With IPv6, each device typically has its own unique public IP. This affects how easy it is for websites to distinguish your devices.
  • VPN behavior: Many older VPNs only route IPv4. If your network has IPv6, traffic to IPv6 destinations can bypass the VPN entirely — an “IPv6 leak”. Modern VPNs either route both or block IPv6 entirely when connected.
  • Geolocation: IPv6 addresses are usually assigned in larger geographic blocks per ISP, which can make city-level geolocation slightly less precise — or sometimes more precise, depending on the database.
  • Port forwarding and hosting: With IPv6, you can directly expose a service on a specific device without NAT tricks. Easier for self-hosting, slightly different security considerations.

Why the Transition Is Slow

Despite IPv4 exhaustion being predicted for decades, only about 40-50% of the internet supports IPv6 in 2026, depending on how you measure. The transition is slow because:

  • The two protocols are not compatible — an IPv4-only client can’t talk to an IPv6-only server without a translator
  • Most existing infrastructure works fine with IPv4 + NAT, so the urgency is limited
  • Enterprise networks have huge investments in IPv4-only configurations
  • Some regions (especially India and parts of Asia) have leapfrogged to IPv6-heavy adoption; others (especially Africa) lag behind

The realistic timeline is “both protocols coexist for the next decade or two, then IPv4 slowly retires”.

What Should You Do?

For most users: nothing. Your devices handle this automatically. Just be aware that:

  • If you set up a VPN, verify it doesn’t leak IPv6 (MyIPInfo can show you)
  • If you self-host services and your ISP gives you IPv6, you may not need port forwarding anymore
  • If a site behaves inconsistently for you and someone on a different network, IPv4-vs-IPv6 routing differences are one possible cause

For developers and operators: support both. Web servers, DNS records, monitoring, and firewall rules should all be designed for dual stack from the start. Treating IPv6 as an afterthought is the source of half the production “but it works on my machine” mysteries.