Which upset.dev Tools Help Check DNS Leaks, VPN Privacy, and Network Exposure?

upset.dev hosts a set of free, browser-based network privacy tools that answer specific questions: whether your VPN is leaking DNS requests, which resolver your browser actually uses, what your IP and browser reveal about you, and what DNS records a domain exposes. They require no installation — you open the page and read the result. The main limitation is scope: these tools report what your connection reveals to the service, so they are diagnostic starting points rather than full audit suites.

DNS Leak Test

The tool is described on the site as answering one question: "Is your VPN really hiding your DNS?" It claims to "expose every DNS server your connection leaks to in seconds."

What it does: When you connect through a VPN, your DNS queries should travel through the VPN tunnel. If they don't, your ISP or another network can still see which sites you visit even though your traffic appears encrypted. This test surfaces the DNS servers your connection is actually reaching.

How to use it:

1. Connect your VPN as you normally would.
2. Open the DNS Leak Test page on upset.dev.
3. Read the list of DNS servers shown.

Expected result: If every resolver listed belongs to your VPN provider or a network you expect, DNS is not leaking. If you see your ISP's resolvers or unfamiliar servers, your DNS traffic is escaping the tunnel.

Common sticking point: A leak result doesn't tell you why. Causes range from VPN configuration (split tunneling, IPv6 handling) to browser-level DNS-over-HTTPS overriding the VPN. Use the edns tool below to narrow it down.

edns — Which Resolver Your Browser Really Uses

The site describes this tool as showing "which DNS resolver your browser really uses, and whether it leaks your network via EDNS Client Subnet."

What it does: Browsers and operating systems can route DNS through different paths — system resolver, browser's built-in DoH, or a VPN's resolver. This tool reports the resolver that actually handled your query. It also checks EDNS Client Subnet (ECS), a DNS extension that can forward part of your IP address to authoritative servers, potentially revealing your approximate network location even when you use a third-party resolver.

How to use it: Open the page and read the resolver identity and ECS status it reports.

Expected result: The resolver shown should match what you intend to use. If you've configured DNS-over-HTTPS in your browser, you should see that provider, not your ISP. If ECS is being forwarded, note that some resolvers strip it and some don't — the result tells you which behavior you're getting.

Why pair it with DNS Leak Test: The leak test shows all resolvers your connection touches; edns shows the one your browser actually prefers and whether it exposes subnet information. Together they distinguish "my VPN leaks DNS" from "my browser bypasses my VPN for DNS."

whoami — What the Internet Knows About You

The site describes this as identifying "what the internet knows about you: IP address, location, network, and browser details."

What it does: It aggregates the fingerprint your connection presents — public IP, approximate geolocation derived from that IP, network/ASN information, and browser characteristics.

How to use it: Open the page and read the reported fields. Run it once with your VPN off and once with it on to compare.

Expected result: With a VPN active, the IP and location should reflect the VPN exit point, not your real location. Differences between the two runs show exactly what the VPN changes — and what it doesn't.

Practical caveat: IP-based geolocation is approximate and can be wrong by a wide margin. Treat the location field as a rough indicator, not a precise address.

Domain Tools — WHOIS and DNS Records

The site describes this as offering "WHOIS and every DNS record type for any domain, all from one simple form."

What it does: For any domain you enter, it returns registration information (WHOIS) and DNS records — the same categories you'd otherwise query across several separate tools.

How to use it:

1. Enter a domain name in the form.
2. Submit and read the WHOIS and DNS record results.

Expected result: You get registration details and the domain's DNS configuration in one view. This is useful for checking whether a domain's mail, nameserver, or TXT records match what you expect — for example, verifying SPF/DMARC-related TXT records or confirming which nameservers are authoritative.

Common sticking point: WHOIS output is often redacted for privacy, so registrant details may be hidden. DNS record results reflect current propagation, which can lag behind recent changes.

Related Tools on the Same Site

Several other upset.dev tools touch network exposure from adjacent angles:

If your concern is interception rather than leakage, "Have I Been MITMed?" is the closer fit. If you want to configure encrypted DNS on Apple devices, the DNS Profile Generator produces the configuration rather than testing it.

How to Choose

• Suspect your VPN isn't hiding your DNS? Start with DNS Leak Test, then use edns to identify which resolver your browser actually uses.
• Want to know your overall exposure? Run whoami with the VPN on and off and compare.
• Investigating a specific domain? Use Domain Tools for WHOIS and DNS records.
• Worried about traffic tampering, not leakage? Use "Have I Been MITMed?"

All of these are browser-based and listed on upset.dev as free tools and services. The site does not state pricing, account requirements, or usage limits for them, so treat availability as subject to whatever the site currently offers when you visit.