Open Port Checker

Check whether a TCP port is open and reachable on a public IP address or host.

Common ports

Processing and privacy

Processing varies by tool. Check the instructions for local processing, server requests, external services and any file or request limits before entering sensitive information.

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Clear instructions

Find steps, examples and limitations below.

Use online

Open the tool in a supported web browser.

Free to use

No sign-up required. Tool-specific limits may apply.

Reference resources

Common Ports Reference
Common service ports with TCP/UDP distinctions and connection-check notes.

How to use the Open Port Checker

Check whether a TCP port is open and reachable on a public IP address or host.

1 Enter a domain or public IP address, or click Use my IP to test your own connection.
2 Enter a port number or click one of the common ports.
3 Click Check port. Open means something accepted the connection; closed or timed out means it is blocked or nothing is listening.

Example and practical tips

After forwarding port 25565 on your router for a Minecraft server, click Use my IP and the 25565 button. If it shows closed, check the router rule, the server’s firewall and that the server is running.

Frequently asked questions

Why is my port closed even though I forwarded it?

Common causes are a firewall on the computer, the service not running, the wrong internal IP in the rule, or an ISP that uses carrier-grade NAT so you have no public IP.

Can I check private IP addresses?

No. The check runs from our server over the internet, so only public addresses can be tested.

How to Use Open Port Checker
Check whether a TCP port is open on a public IP address or domain from the internet. Test port forwarding for games, cameras, servers and more.