TCP

Port Checker

Check whether a TCP port is reachable from the OCS Ping server. Private networks, localhost and reserved addresses are blocked.

Up to 10 ports can be checked in one test.

LEARN

How an online TCP port check works

The Port Checker attempts a TCP connection from the OCS Ping server to the public host and port you specify. An open result means a TCP connection was accepted from this server at the time of the test. A closed or timed-out result can have several causes, including a firewall, NAT rule, filtering or a service that is not listening.

This is an external reachability test. It does not scan private addresses and it does not prove that the application behind an open port is configured securely.

FAQ

Common questions

What does open mean?

It means the OCS Ping server completed a TCP connection to the tested public host and port during that request.

Why does a port time out instead of showing closed?

A firewall or network device may silently drop connection attempts rather than actively reject them.

Does this tool test UDP ports?

No. The current OCS Ping Port Checker tests TCP reachability only.

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