Your VPN is on, the connection icon shows a lock, and you assume your traffic is sealed inside an encrypted tunnel. But right now, a portion of your traffic may be traveling outside that tunnel, exposing your real IP address to the sites you visit.
According to Cisco, global IPv6 traffic reached approximately 48% of all internet traffic by the end of 2024. As IPv6 adoption continues to grow, VPNs that do not properly handle IPv6 traffic can leave parts of your connection unprotected.
IPv6 leaks are not theoretical edge cases. They reflect a gap between how modern internet traffic is routed and how some VPNs handle it. If your VPN does not support IPv6, your protection may not extend to all of your connection.
Why Your VPN Can Be Active and Still Show Your Real IP Address
Most VPN software was originally built around IPv4, the older internet protocol. IPv6, while not new, has only recently become a dominant share of real-world traffic.
When your VPN creates an encrypted tunnel for IPv4 only and your device connects to an IPv6-capable website or service, the IPv6 traffic can bypass the tunnel and travel through your regular network connection, exposing your real IP address to the destination.
Your device runs what is called a dual-stack configuration, meaning it supports IPv4 and IPv6 simultaneously and often prefers IPv6 when the destination supports it.
Research presented at the Privacy Enhancing Technologies Symposium found that many commercial VPN clients leak IPv6 traffic in dual-stack environments, leaving users with the false assumption that all their activity is protected.
How IPv6 Traffic Escapes the Encrypted Tunnel
IPv6 leaks do not happen through a single path. They occur through multiple mechanisms, depending on how your device handles connections, DNS resolution, and background browser activity.
Modern devices and browsers are designed to prioritize IPv6 whenever it is available. A browser algorithm called Happy Eyeballs, built into most operating systems and browsers, attempts IPv6 and IPv4 connections in parallel, often favoring IPv6. When a VPN secures only the IPv4 lane, IPv6 connections can bypass the tunnel and use the unprotected network path.
WebRTC compounds the problem. Even without an active video call, browsers running WebRTC perform STUN requests in the background. These requests can expose your real IPv6 address to third parties without any visible indication that it is happening. The address revealed is tied to your actual network and location.
DNS adds another layer of exposure. When your browser requests a website that supports IPv6, it queries for an AAAA record. If that query resolves and connects over IPv6 outside the tunnel, your real address reaches the destination server while your VPN shows a locked connection on the IPv4 side.
The Exact Data That Gets Exposed During an IPv6 Leak
An IPv6 leak exposes specific pieces of information about your device, network, and activity:
Your real IP address
IPv6 addresses are globally unique and are not masked in the same way as IPv4 behind NAT. Every server receiving your leaked IPv6 traffic sees your real address instead of a VPN-assigned one, which can be linked to your network and general location.
Your physical location
An IPv6 address can reveal your approximate geographic region and network provider. A site receiving your real IPv6 address can often determine your city or surrounding area based on IP geolocation databases.
Your browsing activity
Every site you visit over a leaking IPv6 connection logs your visit against your real IP address rather than your VPN address. Because many websites load third-party resources, that same address can be exposed across multiple services during a single session.
Your VPN use
When a server sees an IPv4 address from a VPN provider alongside an IPv6 address from your real network, it can detect a mismatch. Platforms use this signal to flag sessions, restrict access, or apply additional verification.
Your device and connection signals
A leaking IPv6 connection can expose consistent signals tied to your device and network. Over time, this makes it easier for services to correlate activity across sessions, even when a VPN is active.
How to Check If Your IPv6 Is Leaking Right Now
PureVPN’s IPv6 Leak Test gives you a quick way to check whether your real IPv6 address is escaping the tunnel.
- Make sure you’re connected to a VPN and your VPN session is active.
- Open PureVPN’s IPv6 Leak Test tool in your browser.
- Run the test. It checks both your IPv4 and IPv6 addresses simultaneously.
- Review the result. If your real IPv6 address appears in the output, you have a confirmed leak.
- If only your VPN-assigned address is visible, your VPN is handling both IPv4 and IPv6 traffic as expected.
What to Do If the Test Confirms a Leak
A confirmed IPv6 leak means your current VPN is leaving part of your traffic unprotected. Addressing it requires a VPN that is designed to handle both IPv4 and IPv6 traffic effectively, rather than relying on partial coverage or workarounds.
PureVPN’s IPv6 leak protection routes IPv6 traffic through the encrypted tunnel alongside IPv4. When both protocols travel through the same protected channel, your real IP address is not exposed to destination servers, regardless of whether they operate on IPv4 or IPv6.
PureVPN’s kill switch adds a critical backup layer. If the VPN connection drops for any reason, whether from a network switch, a brief outage, or a Wi-Fi handoff, the kill switch cuts internet access before unprotected traffic can pass through, helping minimize exposure during reconnection
The Lock Icon on Your VPN Does Not Mean Your IPv6 Is Covered
The connection indicator in your VPN client shows that a tunnel is active. It does not confirm which protocols are passing through it. A VPN can appear fully connected while IPv6 traffic still bypasses the tunnel.
IPv6 now accounts for nearly half of all global internet traffic, and that share continues to grow. If your VPN does not cover IPv6, part of your traffic can travel outside the tunnel, exposing your real IP address and location. Run the test. Verify the result. Do not assume the lock icon means full coverage.
