Open port checker
Check whether a TCP port is open and reachable from the internet on any public server, domain or IP address.
What an open port means
A port is a numbered door on a server: websites use 80 and 443, SSH uses 22, mail servers use 25 and 587, and game or camera servers use their own. A port is open when a program on the server accepts connections on it. Closed means the server answered but nothing is listening. No response usually means a firewall silently drops the connection. To check your own home connection, enter your public IP from the What Is My IP tool.
How to use it
- Enter a domain name or public IP address.
- Type a port number or pick a common one.
- Press Check port to see if it is open, closed or filtered.
Frequently asked questions
Why is my port closed after I set up port forwarding?
Check that the program is running and listening on that port, that the forwarding rule points to the right local IP, and that your computer's firewall allows it. Some internet providers also block ports or put customers behind shared addresses (CGNAT), so forwarding cannot work.
Can I check ports on my local network?
No. For safety, this tool only checks public addresses on the internet. Private addresses such as 192.168.x.x can't be reached from outside your network anyway.
Is port checking legal?
Checking a single port on your own server or a public service is normal troubleshooting. Scanning other people's systems without permission is not allowed by our terms, so the tool checks one port at a time and limits how often it can be used.