How do I check if a port is open?

Enter the host and the port number, then run the check. The tool opens a TCP connection from our server and reports whether the port accepted it.

The host is up but the port is closed. Why?

The server is reachable but nothing is listening on that port, or a firewall is blocking it. Confirm the service is running and that the port is allowed through the firewall.

Port checker

Open port checker

Test whether a TCP port is open and reachable on a host, from the public internet. Useful for services like SMTP, SSH, databases, and game servers.

Confirm a service is exposed

A server can be up while the specific port your service needs is closed by a firewall. This tests the port, not just the host.

Checked from outside your network

The test runs from our server, so it reflects what the public internet sees, not what is reachable from your own machine.

Any TCP port

SMTP on 25, SSH on 22, HTTPS on 443, a database, or a game server. If it speaks TCP, you can test its reachability.

Keep watch

Get alerted the moment a port closes

PageWarden can watch a TCP port and alert you if it stops accepting connections, so a firewall change or crashed service does not go quiet.

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Questions

Port checker, answered

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