Port checker
Enter a port — our server will try to connect to it on your address from the outside and tell you whether it is open or closed. Your own public address is checked; you cannot enter someone else's. Common ports: 80 and 443 for the web, 22 for SSH, 3389 for RDP, 8080 for cameras and admin panels.
Detecting your address…
What to do with the result
A port that is open to the outside is probed around the clock by automated scanners, so do not leave factory passwords or standard management ports on your device. If a port does not respond and you need the address for outside access, first find out the address type — whether your IP is white or gray. On a gray address port forwarding is useless: people get around it with proxied access, covered in the article on white and gray IP.
Frequently asked questions
Which address is checked? Your own — the public address your connection uses to reach the internet. You cannot enter someone else's address: this protects against scanning other people's networks. You set the port yourself.
A port is "closed, but the address responds" — what does that mean? The address sent a refusal on that port rather than staying silent. That means the IP is white and reachable from outside; there is just nothing listening on that port. Start the service you need and the port will become open.
A port "did not respond" — why? There is no reply at all: either the port is blocked by a firewall, or the address is gray and incoming connections never reach you. If other ports are silent too, the address is most likely gray — check that separately.
Why does the checker check nothing on a gray address? Behind CGNAT incoming connections are not accepted at all, so there is no point checking a specific port on it — the result will always be 'no reply'.