Most people stumble into this topic after checking their connection and seeing two very different-looking addresses. One is short and dotted. The other is long with colons. Then you wonder if something is wrong, or if you are missing a setting.

Nothing is wrong. You are just seeing two versions of the internet’s address system.

If you want to compare with your own connection as you read, open our IP Lookup tool and look for both IPv4 and IPv6 results.

Two address systems, one goal

An IP address is a routing label. When you visit a site, your device needs an address so the site can send data back to you.

IPv4 is the older system. It uses an IP format like 203.0.113.42, four numbers separated by dots. That format supports about 4.3 billion unique addresses.

IPv6 is the newer system. It uses a longer IP format like 2001:db8:85a3::8a2e:370:7334. The big reason for the longer structure is simple: it supports an enormous number of unique addresses.

In plain terms, IPv6 exists because of IPv4 exhaustion.

Why IPv4 ran out, and how we kept going anyway

The internet grew faster than IPv4 was designed to handle. Phones, smart TVs, game consoles, smart home devices, and business systems all needed addresses. Over time, the pool of spare IPv4 addresses got used up. That is IPv4 exhaustion.

So why does IPv4 still work today? Because providers leaned heavily on a workaround called NAT, short for Network Address Translation.

NAT lets many devices share one public IPv4 address. Your home router is doing this right now. Inside your home network, your laptop and phone have private addresses. Outside your home, websites see a single public IPv4 address for your entire connection.

On mobile networks, providers often use even larger shared pools (carrier-grade NAT). This sharing is one reason why IPv4 can feel crowded, and why some services treat certain IPs as higher risk.

What a IPv6 address looks like (and why it is so long)

A IPv6 address uses hexadecimal characters (numbers and letters) and colons. It is long because it has to be. That length gives IPv6 its massive address space.

For everyday users, the practical difference is that IPv6 can provide more direct addressing without relying on the same heavy sharing used in IPv4. Your connection may still be protected by router and firewall rules, but the routing behavior can be different.

If you see a IPv6 address in a lookup, it usually means your network and device have IPv6 connectivity enabled.

Dual stack: why you often have both IPv4 and IPv6

The internet cannot switch all at once. Too many services still rely on IPv4, and IPv6 adoption has taken years. That is why most modern networks run dual stack.

Dual stack means your device can use IPv4 and IPv6 at the same time. Many systems will try IPv6 first when it is available, then fall back to IPv4 if needed.

This is also why problems can be confusing. A site might work fine over IPv4 but have a broken IPv6 route, or your network might have IPv6 enabled but unstable. That can create the classic “it works sometimes” headache.

A good first step is to check what your connection shows publicly in What Is My IP Address, then compare IPv4 and IPv6 details in your lookup results.

When the difference shows up in real life

Most of the time, IPv4 vs IPv6 is invisible. Browsing works and apps load. But there are a few moments where you might feel it.

VPNs and leaks

Some VPN setups tunnel IPv4 traffic but accidentally leave IPv6 outside the tunnel. That can lead to mixed results where you think your VPN is active, but a service still sees your real network over IPv6. If you use a VPN, run our VPN Leak Test occasionally and confirm both IPv4 and IPv6 behave the way you expect.

Website blocks and endless challenges

Some websites are stricter with certain IP ranges, especially crowded shared IPv4 pools or IPs that look like data center traffic. IPv6 can sometimes avoid that simply because the addressing is less shared, but it depends on your provider and the site’s rules.

Gaming and direct connections

IPv4 NAT can complicate direct connections between players or devices. IPv6 can reduce some of those headaches when everything supports it, but not every game or router setup is consistent, so results vary.

Privacy and security, without the drama

People sometimes hear “IPv6 is unique” and assume it is automatically bad for privacy. The reality is more balanced.

A IPv6 address can be more unique than a shared IPv4 address, which could make it easier for a site to recognize a device over time if nothing else changes. To reduce that risk, many operating systems use privacy extensions that rotate temporary IPv6 addresses for outbound connections.

Security-wise, IPv6 is not magically safer or more dangerous. What matters is configuration. A modern router with sensible firewall defaults can handle IPv6 safely. Problems usually come from misconfigurations or outdated equipment, not from IPv6 existing.

If you want an extra clue about how your IP is labeled on the internet, reverse DNS can sometimes help. You can check that with Reverse DNS Lookup.

How to tell which one you are using right now

If your results show only IPv4, your network may not support IPv6, or it may be disabled.

If your results show both IPv4 and a IPv6 address, you are likely on dual stack.

If you only see IPv6, that is less common, but it can happen on modern networks that use translation services when they need to reach IPv4-only destinations.

FAQs

Why do I see two IPs?

Most likely you are on dual stack, so your device has both IPv4 and IPv6 connectivity.

Is IPv6 faster than IPv4?

Not always. Speed depends on routing and ISP setup. Some networks route IPv6 more efficiently, others do not.

Should I turn off IPv6?

Only as a troubleshooting test. Long term, it is usually better to keep IPv6 enabled and configured correctly.

How do I know if my VPN is leaking IPv6?

Run a leak test and confirm your visible IPv6 address changes when the VPN is on, or that IPv6 is fully handled inside the tunnel.

Final take

IPv4 vs IPv6 is mostly a story about growth. IPv4 hit limits because of IPv4 exhaustion, and IPv6 provides the address space the modern internet needs. Most users will remain in a dual stack world for years, with devices quietly choosing the best available route.

If you want to stay confident, keep it simple: check what your connection exposes, confirm your VPN handles IPv6, and use your IP results as a practical troubleshooting tool instead of a mystery.