Connection tools
46 tools that run in your browser. Nothing to install, nothing uploaded.
Every one of these connection tools runs in your browser or against public resolvers — none require an account, and none upload your files. They cover the two things people actually need to check: what your connection reveals about you (your IP, location and network operator, read at our edge) and whether a domain’s DNS and mail records are set up correctly. The DNS tools query two independent public resolvers so you can see where they disagree, which is the honest version of a propagation check.
- Proxy / VPN Signal CheckCheck whether your traffic is being rerouted — and see what sites see.
- Bandwidth ConverterConvert between Mbps, MB/s and everything in between.
- Bufferbloat / Latency Under Load TestFind out whether your connection falls apart when somebody else is downloading.
- CAA Record CheckerSee which certificate authorities are allowed to issue for a domain.
- Which CDN Datacenter (colo)See which Cloudflare data centre is serving you.
- CNAME Chain TracerTrace a domain’s CNAME alias chain to where it finally points.
- My Connection ReportEverything the edge can see about your connection, on one page.
- Connection Stability MonitorWatch a connection over time and catch the stalls a speed test never sees.
- Data Usage CalculatorEstimate monthly data use, and find what is really consuming it.
- Disposable Domain CheckerSpot disposable addresses — and the plus-tag trick a blocklist never catches.
- DKIM Selector CheckerLook up a DKIM key by selector — and see why a selector cannot be guessed.
- DMARC Record CheckerLook up a domain’s DMARC policy and see how strictly it is enforced.
- DNS Lookup (all records)Query any DNS record type against two independent resolvers and compare their answers.
- Is It DNS or the Connection?When something will not load, find out which of the two layers is broken.
- DNS Resolver Speed RaceTime the public DNS resolvers on names none of them have cached.
- DNSSEC Validation CheckCheck DNSSEC properly — including the broken-signature case a single query cannot see.
- Download Time CalculatorEstimate how long a file takes at a given connection speed.
- ECH / Encrypted SNI CheckCheck whether this connection encrypted the server name — the part TLS leaves in the open.
- Email Header AnalyzerRead a message's route and its authentication — including whether it aligns.
- Email Syntax ValidatorCheck an email address against the actual RFC rules — and see what syntax cannot tell you.
- Global DNS Propagation CheckReal dig queries from six countries, so 'has it propagated' gets a real answer.
- Global Ping TestReal ICMP pings to your host from machines on five continents.
- HTTP/2 vs HTTP/3 CheckCheck whether your connection is using HTTP/3.
- Download Speed TestDownload speed, and what it actually supports — which is the question behind it.
- IPv6 Connectivity TestFind out whether this connection actually used IPv6 — not whether it could.
- Is This Site Down?Check whether a site answers from outside your own network.
- LAN Scanner (What's on My Network)See which devices on your network answer a browser. An estimate, not a scan.
- MX Record CheckerFind the mail servers a domain uses, in priority order.
- HTTP Headers EchoSee every header your browser sends before a site runs a single line of JavaScript.
- IP Location LookupSee the location your IP address reveals — and how rough that guess really is.
- ISP / ASN LookupFind out which network your traffic actually belongs to.
- Screen Resolution & DPIYour resolution has three different answers — see all of them and why they differ.
- My User AgentSee exactly what your browser announces to every site you visit.
- Network Problem Finder (guided)A few questions that narrow a network problem to the layer it is actually on.
- NS / Nameserver LookupSee which nameservers are authoritative for a domain.
- Online TracerouteA real traceroute from a machine in the region you choose, hop by hop.
- Page Load Timing (your connection)Where the time went loading this page — DNS, connection, TLS, server and transfer.
- Latency & Jitter MeterLatency and jitter, measured properly — the numbers a speed test hides.
- Reverse DNS (PTR)Find the hostname an IP address resolves back to.
- Router Log InterpreterFind the entries in a router log that matter — and ignore the ones that fill it.
- TXT / SPF ViewerRead a domain’s SPF record and see which servers may send its mail.
- TLS Version & Cipher ViewerSee the TLS version and cipher suite this connection actually negotiated.
- Upload Speed TestUpload speed — the half of the connection that breaks calls and backups.
- Video Call Readiness TestWhether your connection will hold up on a call — measured on the things that matter.
- What Is My IPThe address the internet sees when you connect.
- Wi-Fi Scan Report InterpreterRead a Wi-Fi report and understand signal, noise and channel choice.
Two different jobs live in this category
Half of these tools look outward at your own connection: the address and network operator the internet sees, the route your traffic takes, latency and jitter, throughput up and down, and whether the line falls apart when somebody else in the house starts a download. The other half look at a domain’s public records: which nameservers are authoritative, where a CNAME chain finally lands, which mail servers accept its mail, and what its SPF, DMARC and CAA records permit. They share a page because they answer the same practical question from opposite ends — when something will not load or mail will not arrive, the fault is either your connection or the other side’s configuration, and these tell you which.
Why speed is rarely the number that matters
Almost everyone reaches for a speed test, and for almost every complaint it is the wrong measurement. Video calls, gaming and general responsiveness are decided by latency, jitter and loss, not by peak throughput — a 500 Mbps line with 200 ms of jitter under load is a worse call than a 30 Mbps line that stays steady. The specific failure behind most “my internet is fine but calls break up” reports is bufferbloat: throughput is fine, but the moment the link is saturated, latency climbs by hundreds of milliseconds because an oversized buffer refuses to drop anything. Run the latency and bufferbloat tests before the speed test, and you will usually have your answer already.
What a DNS check here can and cannot prove
The lookup tools query independent public resolvers over DNS-over-HTTPS and show you each answer side by side, which makes them conclusive in one direction and suggestive in the other. If two resolvers return different records, the change is genuinely still propagating and you have proof. If they agree, all you have learned is that these resolvers agree — your ISP’s resolver, a corporate resolver, or a stale cache on your own machine can still be serving the old record until its TTL expires. That is why nothing here is labelled a global propagation check: to make that claim honestly you would need to query resolvers on every continent, and the tools that claim it mostly do not.
Where these measurements are weaker than the native tools
A browser cannot send an ICMP packet, so nothing here is ping in the strict sense — latency is measured with timed HTTPS requests, which include TLS and server handling and therefore read a little higher and a little noisier than the ping command on your own machine. Throughput is measured against one endpoint over one set of connections, so it is a floor rather than a ceiling for what your line can do. Where the difference matters, use these to establish that a problem exists and roughly where, then reach for ping, traceroute, mtr or dig to characterise it precisely. Several tools here exist specifically to make the output of those commands readable once you have run them.
Frequently asked questions
Is this the same as the ping command?
No. A browser cannot send ICMP packets, so latency here is measured with timed HTTPS requests, which carry TLS negotiation and server processing on top of the round trip. Expect readings a little higher and a little noisier than ping on the same connection. The relative picture — is latency stable, is jitter high, does it collapse under load — is still accurate, which is what the diagnosis actually turns on.
My speed test looks fine but calls still break up. What should I check?
Latency, jitter and bufferbloat, in that order. Real-time media cares about consistency far more than peak throughput, and the classic pattern is a connection that tests at hundreds of megabits and adds hundreds of milliseconds of delay the moment anything saturates the uplink. Run the bufferbloat test while nothing else is downloading, then again during a large upload — if latency climbs sharply, that is your answer, and it is usually fixable with smart queue management on the router.
Do the DNS tools show global propagation?
They query independent public resolvers and show each answer, which proves a change is still in flight when the answers differ. Agreement is weaker evidence: your ISP’s resolver, a corporate resolver or a cache on your own machine can still serve the old record until its TTL runs out. Nothing here is labelled a global propagation check, because making that claim honestly would need resolvers on every continent.
Why does my IP location show the wrong city?
Because IP geolocation is an inference from registry data and network routing, not a measurement. Accuracy is usually good at country level, unreliable at city level, and can be wildly wrong when your traffic exits through a carrier-grade NAT, a mobile network or a VPN — the address is then registered wherever that infrastructure lives, which may be hundreds of miles away. The tool reports its confidence rather than presenting a pin as fact.