IPv6 leaks are a reason for concern for many people who choose to employ the services of a virtual private network application. A VPN client that has IPv6 support guarantees that your IPv6 address will not be exposed to visited websites when connecting to a server through the VPN tunnel.
Some might argue that you need a VPN with IPv6 compatibility only if you actually have an IPv6 address. But that’s not necessarily true. Nevertheless, you can start by understanding the differences between IPv4 and IPv6 before proceeding further.
IPv4 and IPv6 addresses
ISPs are responsible for assigning IP addresses to every device that connects to the Internet. IP addresses are unique identifiers that may correspond to not only individual devices but also entire networks of subnetworks of devices.
Currently, the information superhighway is dominated by IPv4 addresses. These are 32-bit addresses whose format looks like 192.168.0.1. Meanwhile, IPv6 addresses were created to eventually supersede IPv4 addresses.
IPv6 provides more address space (128 bits) to cover the significant increase of Internet-enabled devices. The 192.168.0.1 IPv4 address converted to IPv6 looks like ::ffff:c0a8:0001 (short) or 0000:0000:0000:0000:0000:ffff:c0a8:0001 (long)
Issues with transitioning to IPv6
IPv4 and IPv6 addresses are not directly interoperable, which means that a special technology must be implemented by Internet Service Providers to migrate from IPv4 to IPv6.
Unfortunately, few telecom providers are willing to adopt IPv6 because the migration technology is expensive for both network hardware and software. It also means performing a thorough investigation of unsupported applications and infrastructure, which takes time.
Nevertheless, there are some major ISPs, web companies and home-networking equipment manufacturers which have permanently activated IPv6 for their products and services. Among this list are Google, Facebook, Comcast, D-Link, AT&T, and Cisco.
Do you need a VPN with IPv6 support?
Yes, if you have an IPv6 address.
A VPN that is “IPv6-enabled” means that it’s equipped with the necessary tools for protecting your online anonymity when it comes to your IPv6 address. If your virtual private network service cannot handle IPv6, then you will face recurrent leaks, which is one of the reasons why users turn to VPNs in the first place: privacy and security.
What if you only have an IPv4 address?
According to Google, only 30% of worldwide Google users have IPv6 connectivity. But most users with IPv6 continue to have IPv4 addresses, too. IPv6-enabled systems typically prefer IPv6 connections over IPv4.
You might not have an IPv6 address now, so there’s no need to use a VPN tool with IPv6 address. However, you should consider it anyway on the long term. As more and more ISPs slowly transition from IPv4 to IPv6, you will eventually receive an IPv6 address, which means you will eventually need protection from a VPN service that’s compatible with IPv6.
Why do you need a VPN with IPv6 support?
All VPN clients work with IPv4 addresses, but few are and compatible with IPv6. If you have both IPv4 and IPv6 addresses, it means that the virtual private network service must protect two types of addresses.
Subsequently, a VPN tool without IPv6 might successfully protect your IPv4 but will compromise your IPv6 address. It’s enough to expose only one address to reveal your sensitive information.
The point is that it’s best to have a VPN service that supports both IPv4 and IPv6 addresses. Even if your home or office network doesn’t have IPv6, keep in mind that you might travel to a new place, bring your laptop, connect to the Wi-Fi, and launch your VPN client. After running an online test, it might be revealed to you that your connection does, in fact, support IPv6. Therefore, your VPN service should support IPv6, too.
Which VPN services offer IPv6 leak protection?
As previously mentioned, most VPN services can protect your privacy by masking your IPv4 address. However, few of them have implemented a special technology capable of blocking requests made by remote servers to identify your IPv6 address: IPv6 leak protection. An independent study ran in 2015 shows that 10 out of 14 VPN providers cannot prevent IPv6 addresses from being leaked.
The following virtual private network clients have been reviewed by our team. Currently, these are the top-ranked VPNs on FindYourVPN.com that include an explicit setting to prevent IPv6 leaks:
- ExpressVPN: Options -> Advanced -> Prevent IPv6 leak protection while connection (enabled by default)
- Ivacy: Settings -> General -> IP/DNS leak protection (includes both IPv4 and IPv6)
- Private VPN: Advanced -> Connection Guard tab -> IPv6 Leak Protection
- IPVanish: Settings -> Connection -> Enable IPv6 Leak Protection
- PureVPN: Preferences -> Advanced Options -> Security -> IPv6 Leak Protection
Some applications like CyberGhost VPN have another solution for preventing IPv6 leaks: disabling incoming and outgoing IPv6 connections altogether. But the downside here is that you will not be able to access online resources which are exclusively available through IPv6.
Another good idea is to find a VPN service that’s transparent about its IPv6 servers, including bandwidth utilization reported in real time (to avoid bottlenecks), like Perfect Privacy.
How to test for IPv6 leaks?
It’s easy to test your Internet connection for IPv6 leaks, thanks to the fact that there are so many online services capable of doing this. Just follow these steps:
- Without launching your VPN client, visit a website like IPLeak and check out your IPv6 address
- Start your VPN service, connect to any server, and make sure that you have successfully connected
- Revisit the same website as before and check your IPv6 address:
- If it’s the same as before, then your VPN tool isn’t working properly or doesn’t have IPv6 support
- If you receive an error that says “IPv6 test not reachable”, then your IPv6 address is protected by your VPN
Note: If you frequently travel and connect to the Internet from new hotspots, make sure to regularly test your connection to see if you got associated with an IPv6 address. This way, you can know for sure if you need to activate IPv6 leak protection in your VPN.
Even if you don’t currently have an IPv6 address, you will probably get associated with one soon. When that happens, it’s imperative for your VPN to offer full protection against IPv6 leaks. This way, you don’t risk exposing your real information when accessing IPv6 servers.