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Documentation Core Tools TCP Port Scanner

TCP Port Scanner

TCP Port Scanner

Check whether common TCP ports on a public hostname or IPv4 address accept a connection from our side—useful for quick reachability checks when you own or are allowed to test the target. Results update live on the page.

What this tool is for

Use the TCP Port Scanner when you want a fast, readable answer to: “From this site’s environment, can we open a TCP connection to that host on these ports?” Typical uses include checking exposed services, comparing what you expect to be open versus what actually answers, and learning how port lists behave on well-known public practice hosts.

The check is not run from your personal laptop’s network alone—it reflects reachability from the same network path this website uses for the scan feature. That is why results can differ from what you see with a terminal on your home connection.

Use it responsibly

  • Only scan hosts you own or have explicit permission to test.
  • Private addresses, loopback, and similar targets are blocked to reduce misuse.
  • Aggressive or unauthorized scanning may be limited or blocked.

How to use the page

  1. Enter a public hostname (for example a well-known practice host) or a public IPv4 you are allowed to probe.
  2. List ports separated by commas or new lines, or use a range like 8000-8010.
  3. Adjust the per-port wait time if needed (within the limits shown on the page).
  4. Start the scan and watch the table fill in as each port is classified open or closed / filtered, with a round-trip time when a port accepts a connection.
  5. Examples can load safe public targets or fill in default ports for common software names—those shortcuts only change the port field; you still choose the host yourself.

Presets drop in popular port bundles (for example common services or web stacks) so you do not have to type long lists by hand.

Understanding the results

  • Open means a TCP connection could be completed within the timeout—something on that port accepted the handshake.
  • Closed / filtered means no successful connection in time: the port may be closed, firewalled, or filtered from this path.
  • The tool does not identify which application is listening; it only reports reachability.

Limits you should know

  • You can scan up to two hundred distinct ports in one run.
  • IPv6-only targets are not supported in this version—use a name that resolves to IPv4 or enter an IPv4 address.

Recent scans and privacy

Finished scans can be saved in recent scans on your device so you can reopen the same host and ports quickly. That history stays in your browser storage for convenience and is not described here as a separate product beyond this page.

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