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Why Are VPNs Susceptible to IPv6 Leaks?

VPNs normally do a great job of protecting your privacy on the Internet. But did you know they can actually compromise it if they suffer IPv6 leaks?

If you’re not familiar with them, I’ll tell you all you need to know – a quick intro to IPv6, how leaks put your data at risk, how to check for IPv6 leaks in your VPN, and how to protect yourself.

First Things First – What Is IPv6?

The easiest way to think of IPv6 is as the successor to IPv4 – the current IP address format.

But instead of a simple format like 3.3.3.3 like IPv4 has, IPv6 takes it to the next level with two more complex address formats:

  • The pure format: x:x:x:x:x:x:x:x. “x” can be any hexadecimal value between 0 and FFFF.
  • The dual format: x:x:x:x:x:x:y:y:y:y. “x” can be any hexadecimal value between 0 and FFFF, and “y:y:y:y” can be an IPv4 address.

Here’s an example of how an IPv6 address looks like: 5005:0ab7:0000:0000:0000:8b5d:0540:7228

Are complicated IP addresses like that really necessary?

Yep – we actually ran out of IPv4 addresses. And IPv6 will take care of that problem by offering around 340 new undecillion addresses (so around 340 trillion trillion trillion IP addresses).

So What Are IPv6 Leaks & Why Do They Happen?

Here’s the thing about IPv6 support – it’s still pretty limited. Only a little over 25% of networks advertise IPv6 support. Not a lot of websites and online services support it either.

And those services likely include your VPN provider. But your ISP might support IPv6, which means you’ll get both an IPv4 and an IPv6 address.

If the VPN doesn’t have IPv6 support, a leak will occur because it will ignore your IPv6 traffic. The VPN will only route your IPv4 traffic through the encrypted tunnel. In that situation, your IPv6 address is exposed, meaning that:

  • Websites and advertisers can use it to track you online.
  • Websites can restrict your access to content with geo-blocks.
  • People can use it to find out details about where you live (country, city, ZIP code, ISP).
  • You might not be able to bypass firewalls that add blocking rules to IPv6 addresses.

How Can You Detect an IPv6 Leak?

Unfortunately, there are no clear signs you can look for. I guess it would be safe to assume you’ll suffer IPv6 leaks if you have an IPv6 address, and your VPN provider told you they don’t support IPv6 traffic.

But that’s hardly concrete info.

Luckily, there is a simple tool you can use to check for IPv6 leaks in your VPN. Just click that link and follow the steps. In a few seconds, you’ll quickly find out if there are any problems.

What’s more, ProPrivacy’s tool will also tell you if there are any:

  • IPv4 leaks
  • DNS leaks
  • WebRTC leaks

Best of all – if you do find out you’re dealing with any kind of leak, there is a link to a very useful guide on the tool’s page that will tell you how to solve the issue.

How to Prevent IPv6 Leaks

Really, there are only two things you can do to make sure IPv6 leaks don’t put your data in danger – disable IPv6 or use a VPN with built-in IPv6 leak protection.

1. Disable IPv6

IPv6 might be a hell of a headache, but you can actually easily disable it on your device if you want. Here are some quick guides on how to do it on most operating systems:

  • Mac OSX – Head to System Preferences> Network. Pick the first connection on the list, click Advanced, and choose “Link-local only” or “off” for Configure IPv6.
  • Windows 7 – Go to Control Panel> Network and Internet> Network and Sharing Center, and click on Local Area Connection (or what you named your primary connection). Then hit Properties and uncheck the “Internet Protocol Version 6 (TCP/IPv6)” option.
  • Windows 8 – From the Start Menu, go to Desktop and right click on Networks icon. Now, click “Open Network and Sharing Center,” and select your primary connection (Local Area Connection). Click Properties and uncheck “Internet Protocol Version 6 (TCP/IPv6).”
  • Windows 10 – Right-click the network icon on your desktop and click “Open Network and Sharing Center.” Pick “Change adapter settings” on the right, right-click on your primary connection, choose Properties, and uncheck “Internet Protocol Version 6 (TCP/IPv6).”
  • Android – Head to Settings> Connections> Mobile networks> Access Point Names. Pick your mobile operator, and scroll down until you reach “APN protocol.” Tap on it and choose IPv4.

By the way, quick info for Windows users – if you really know your way around the system, you can use this fix from Microsoft to disable IPv6 completely.

2. Use a VPN with IPv6 Leak Protection

Besides disabling IPv6, you should also use a VPN that has built-in IPv6 leak protection. That basically just means the VPN will automatically block IPv6 traffic to protect you from leaks.

Some decent options include:

What If I Don’t Want to Disable IPv6?

That’s understandable. If you disable it or use a VPN that blocks IPv6, you won’t be able to connect to websites that only use IPv6 addresses.

Well, in that case, your best bet is to use a VPN service that actually supports IPv6 traffic. They can do that through dual stack configuration – basically offering support for both IPv4 and IPv6 to offer a seamless experience.

There aren’t a lot of VPNs that have this feature, but some decent options include HIDEme and Perfect Privacy.

Conclusion

VPNs are a great way to secure your privacy, but you need to make sure they don’t suffer leaks – especially IPv6 leaks which are pretty simple to avoid.

Do you know other ways people can protect themselves against VPN leaks? Or other tools people should use to check for IPv6 leaks? Go ahead and share your thoughts with the rest us.

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