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Privacy explained

VPN Leaks Explained: DNS, IPv6, IP and WebRTC

A VPN is supposed to carry protected traffic through the tunnel. A “leak” means some information takes a different path than the user expected.

What people mean by a VPN leak

When a VPN is connected, the expectation is that traffic meant to use the VPN follows the protected path. A leak is a situation where some network information or traffic is exposed outside the path the user expected.

Different leak names describe different technical causes.

DNS leaks

DNS helps translate website names into network addresses. If DNS requests leave through the ordinary network instead of the protected VPN path, the local network or provider may gain information about names the device is trying to reach.

A well-configured VPN should handle DNS consistently with the intended privacy model.

IPv6 leaks

Modern networks can use both IPv4 and IPv6. If a VPN protects IPv4 traffic but leaves IPv6 using the normal connection, part of the device’s traffic may bypass the expected path.

That is why dual-stack handling matters on networks where IPv6 is available.

Public IP leaks

If a site can still discover the normal public IP address when the VPN is supposed to hide it, the privacy benefit is reduced.

A simple before-and-after IP check can help confirm that ordinary web traffic is exiting through the VPN endpoint.

WebRTC exposure

Browsers use WebRTC for real-time communication. In some configurations, WebRTC has historically exposed network-address information in ways users did not expect.

Modern browsers and VPN applications have improved considerably, but the term remains common in VPN privacy discussions.

Why leak testing matters

A VPN connection can look connected while a secondary protocol or name-resolution path behaves differently. Testing gives the user evidence that the connection is operating as expected.

The goal is not paranoia; it is consistency between what the interface says and what the network actually does.

What a user should expect when the VPN says “connected”

A normal user should not have to think separately about IPv4, IPv6, DNS and browser real-time networking every time the VPN starts. The expectation is simple: traffic that is supposed to use the VPN should follow the protected path consistently.

That is why leak prevention and testing are meaningful product-quality questions rather than obscure technical trivia. They are ways of checking whether the real network behavior matches the simple promise shown by the connection status.

Frequently Asked Questions

What is a DNS leak?

It means DNS requests are using a path outside the protected route the user expected, potentially exposing name-resolution activity.

What is an IPv6 leak?

It occurs when IPv6 traffic bypasses the VPN even though the user expects all supported traffic to use the tunnel.

How can I check my VPN IP?

Compare the public IP before connecting and after connecting. The VPN site already provides a guide for checking the public VPN IP.

Are VPN leaks common?

Good modern VPN clients are designed to prevent them, but configuration and network differences make testing useful.

Related reading

What Does a VPN Protect?

A plain-English explanation of the practical benefits of putting an encrypted VPN path underneath everyday internet use.

ZBEVPN is available from the Download page for readers who want a VPN client.

Independent ZBEVPN IPv4, IPv6 and WebRTC evidence

For a concrete example, ZBEVPN published an August 26, 2026 external verification showing before-and-after public-IP results, working IPv4/IPv6 VPN egress and a BrowserLeaks No Leak WebRTC result.

Inspect the independent ZBEVPN verification artifacts.

Published ZBEVPN IPv4, IPv6 and WebRTC results

Rather than relying only on design claims, ZBEVPN publishes independently observable evidence for IPv4/IPv6 VPN egress and WebRTC public-IP behavior.

View the August 26, 2026 verification results.