Open port checker
Enter a port number - we will try to connect to it from the internet at your IP address and show the result.
What the tool checks
The Prokso server tries to open a TCP connection to your external IP address on the port you enter - just as anyone on the internet could. Only the address you opened the page from is checked: you cannot enter someone else's IP. One check is one port, and there are at most 10 checks per minute.
A port is the number of a "door" on a device behind which a particular program works: a web server on 80 and 443, SSH on 22, Windows Remote Desktop on 3389. The address websites see is shown on the My IP page.
What the result means
| Result | What it means |
|---|---|
| Open | Something answers on the port, and the whole internet can see it. Make sure it is your program and that it is protected by a password. |
| Closed | The device or router refused the connection: no program is listening on this port. |
| No answer | The packets are dropped by a firewall, the router or the ISP. That is good for security. |
Why a port is closed even though the program is running
At home there is a router between your computer and the internet. It shares one external address among all devices through NAT and does not let incoming connections through until you set up port forwarding. Mobile networks and many ISPs use CGNAT: the external address is shared by hundreds of subscribers, and you cannot open a port on it for yourself.
Proxies and ports: opposite directions
This tool checks incoming connections to you. A proxy works the other way round: your program connects to the gw.prokso.com gateway on ports 823, 824 or 10000-20000 itself. You don't need to open any ports on your router for that. If the connection to the proxy fails, test the line in the proxy checker: office networks sometimes block outgoing connections to non-standard ports.
FAQ
Can I check a port on someone else's IP address?
No. The tool checks only the address you opened the page from, so it cannot be used to scan other people's networks.
Why is the result "No answer" rather than "Closed"?
A firewall or router silently drops the packets instead of refusing the connection. That is even better for security: from outside nobody can tell whether there is a device at the address.
Do I need to open ports to use a proxy?
No. Your program connects to the proxy with an outgoing connection, so no incoming ports on your router are needed.
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