Port Check
Is a TCP port reachable from multiple global probes? Checks any host:port combination from 6 probes worldwide and shows connect-time per probe — useful for confirming firewall rules, load-balancer health, and anycast reach.
How to Use
- Enter a host:port target — example.com:443, 1.1.1.1:80, or pick a preset.
- Each probe attempts a TCP connection + HEAD request. TCP connect time > 0 means the port is reachable.
- Open ports show connect time; closed / filtered ports show "failed".
| Probe | Status | TCP connect | Total | Resolved IP |
|---|
Enter host:port above — TCP reachability from each probe lands here in a few seconds.
What gets measured
About the Port Check
The Port Check is a free tool for networking and IP tasks. It runs right in your web browser, so there is nothing to download. Is a TCP port reachable from multiple global probes? Checks any host:port combination from 6 probes worldwide and shows connect-time per probe — useful for confirming firewall rules, load-balancer health, and anycast reach.
How it works
Enter what you have and read the result as it updates live. It all runs on your own device, so it is quick and private, with nothing to install.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
Frequently Asked Questions
Does this work for non-HTTP ports?
Yes — the tool checks the TCP handshake (timings.tcp). If the port is reachable, you'll see a connect time even if the service isn't HTTP. Non-HTTP ports will show "failed" at the protocol level, but the port status is based on whether TCP connected.
Why can't I scan arbitrary ranges?
This tool checks ONE port at a time across multiple probes — the use case is "is this service reachable worldwide?", not port scanning. We don't offer mass scanning because many networks prohibit it and it's abusive.
Is this legal?
Checking a single port on a host you control or use is fine. Scanning infrastructure you don't own can be illegal in some jurisdictions. Don't.
How do I use the Port Check?
Simply type your numbers and read the result, which refreshes the instant you change something. There is nothing to submit and nothing to wait for.
Is it free? Does it work without internet?
Yes to both. It is free with no sign-up, and once the page has loaded it keeps working even with no internet.
Where does my data go?
Nowhere — every calculation runs on your own device. Nothing you enter is uploaded, logged, or stored.
Common Use Cases
Check firewall exposure
See if a port is inadvertently open on your server from unexpected regions.
Verify load-balancer
Confirm all health-check endpoints are reachable from every probe.
Test a new deployment
New service up? Make sure it's reachable before announcing.
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