Free DNS Leak Test — Check If Your VPN Is Leaking DNS Queries

ProxyDime's DNS Leak Test detects whether your DNS queries are being routed outside your VPN or proxy tunnel and exposed to your ISP or third-party DNS resolvers. Run a standard test in seconds or launch an extended test that samples a wider range of resolvers over approximately 30 seconds for more thorough detection. The tool identifies every DNS server responding to your queries and flags any that belong to your ISP rather than your VPN provider — a clear indicator of a DNS leak.

If your VPN is leaking DNS traffic, your ISP can see every website you visit — even if your IP address appears masked. DNS leaks are one of the most common and overlooked privacy vulnerabilities for VPN users, and they often occur without any visible sign of a problem. This test gives you definitive proof of whether your DNS traffic is actually protected.

What Is a DNS Leak?

A DNS leak occurs when a device running a VPN or proxy sends DNS resolution requests — the queries that translate domain names like google.com into IP addresses — outside the encrypted VPN tunnel to a DNS server the user did not intend to use, typically one operated by the user's ISP. The VPN masks the user's IP address for regular traffic but the DNS queries bypass the tunnel entirely, revealing every domain the user visits to their ISP.

DNS leaks are particularly insidious because the VPN connection appears to be working normally — the user's visible IP changes to the VPN server's IP — but the browsing activity is still fully exposed at the DNS layer. This completely negates the privacy protection the VPN is intended to provide.

How Does a DNS Leak Happen?

DNS leaks most commonly occur due to the following conditions:

Misconfigured VPN Client: When a VPN is improperly configured, the operating system's default DNS settings (pointing to ISP DNS servers) may remain active alongside the VPN's DNS configuration. The system then sends DNS queries through whichever resolver responds first — often the ISP's.

VPN Without Its Own DNS Servers: Some VPN services do not operate their own DNS infrastructure and instead rely on external resolvers. If those resolvers are not routed through the VPN tunnel, every DNS query leaks by design.

IPv6 DNS Leaks: VPNs that protect IPv4 traffic but leave IPv6 DNS resolution unprotected will leak IPv6 DNS queries on networks that support IPv6 — a common oversight in consumer VPN clients.

WebRTC and Smart Multi-Homed Name Resolution (SMHNR): On Windows systems, a feature called Smart Multi-Homed Name Resolution sends DNS queries to multiple resolvers simultaneously for faster resolution, bypassing VPN DNS settings.

What Is the Difference Between Standard and Extended DNS Leak Tests?

The Standard DNS Leak Test sends a small batch of DNS resolution requests to ProxyDime's test infrastructure and identifies which resolvers respond. It completes in a few seconds and is sufficient for most users checking a single VPN configuration.

The Extended DNS Leak Test runs a significantly larger set of randomized DNS requests — sampling a broader range of resolvers — to detect intermittent or partial leaks that the standard test might miss. The extended test takes approximately 30 seconds. It is recommended for users who want to audit complex network setups, multi-hop VPN configurations, or enterprise environments with custom DNS policies.

How to Interpret DNS Leak Test Results

No Leak Detected: All DNS responses are coming from your VPN provider's DNS servers or a trusted third-party resolver you configured (e.g., Cloudflare 1.1.1.1 or Google 8.8.8.8 routed through the VPN). Your DNS traffic is properly tunneled.

Leak Detected: One or more DNS responses are coming from servers operated by your ISP or an unrelated third party outside your VPN's network. This means your browsing activity is exposed at the DNS layer despite the VPN connection.

Mixed Results: Some DNS responses come from your VPN and others from outside sources. This indicates a partial leak — possibly caused by IPv6 traffic bypassing an IPv4-only VPN tunnel.

How to Fix a DNS Leak

If the ProxyDime DNS Leak Test detects a leak, here are the steps to remediate it:

Enable DNS Leak Protection in Your VPN Client — Most reputable VPN apps include a DNS leak protection toggle. Enable it and re-run this test.

Manually Configure DNS Servers — Set your network adapter's DNS to your VPN provider's DNS servers rather than the ISP-assigned default.

Disable IPv6 If Not Protected — If your VPN only tunnels IPv4 traffic, disable IPv6 on your network adapter to prevent IPv6 DNS leaks.

Use a VPN With Its Own DNS Infrastructure — Choose a VPN provider that operates its own zero-log DNS servers and routes all queries through the tunnel.

Set Up a Firewall Rule — Block all DNS traffic (UDP/TCP port 53) except to your VPN's DNS server using a system firewall or router rule.

Frequently Asked Questions About DNS Leaks