New. DNS Leak Test

edns.upset.dev

See what DNS resolver your browser is really using, and whether it leaks your network via EDNS Client Subnet.

resolving...

About

edns.upset.dev tells you what DNS resolver your device is really using, and whether it shares part of your network address with the websites you visit. Run the check and see for yourself.

How it works

A lookup happens in three steps.

01

Run the check

Start a lookup straight from your browser. Nothing to install, no account to create.

02

We watch the lookup

Your device asks its DNS resolver to find a one-time address that only we answer, so we see exactly who asked.

03

See the result

We show you the DNS resolver that did the lookup and whether it shared part of your network along the way.

Use cases

What people reach for edns to figure out.

DNS leak testing

Confirm a VPN or encrypted DNS is actually routing your queries, not silently falling back to the ISP resolver.

ECS privacy audit

See whether your resolver forwards an EDNS Client Subnet, exposing a slice of your network to upstream authoritative servers.

CDN routing debugging

Understand which resolver and subnet a CDN sees when deciding which edge location to send you to.

Resolver verification

Check that a custom DoH or DoT profile resolves through the resolver you configured, from any device.

Features

What ships in the service.

  • Live resolver IPShowing you what DNS resolver you are currently using.
  • ECS detectionTells you when your resolver shares part of your network with the sites you visit.
  • JSON APICORS-enabled JSON, usable from a browser, curl, or a script.
  • No sign-upFree to use with no account or API keys required. Rate limits may apply.
  • Works anywhereCheck from any device, browser, or network.

API

Free, CORS-enabled, no authentication required.

curl
curl -L https://edns.upset.dev
JavaScript
const res = await fetch("https://edns.upset.dev/");
const { dns, edns } = await res.json();