Port Checker
Check whether a public TCP port accepts connections.
A port check attempts a TCP connection to a host and port from a remote probe. If it connects, the port is open and something is listening; if it is refused or times out, either nothing is listening or a firewall is blocking the attempt.
Start a check
Public internet targets onlyResults
Ready when you are
Enter your details above and run the tool.
How Port Checker works
What it does
Check whether a public TCP port accepts connections.
What you get
Whether a remote probe can establish a TCP connection to the port.
Live data sources
The target is sent to a network provider. Results include their source; timeouts and unavailable data are clearly marked.
What if a check cannot finish?
Confirm your input and try again. A timeout, blocked request, or unavailable provider is not proof that a domain is broken. Internet measurements and third-party services have limits.
Port Checker — frequently asked questions
What is the difference between refused and timed out?
Refused means the host answered and nothing is listening on that port. Timed out means nothing answered at all — usually a firewall dropping the packet silently.
The port is open locally but closed here. Why?
Something between the probe and your service blocks it: a router without port forwarding, a cloud security group, a host firewall, or a service bound to 127.0.0.1 rather than all interfaces.
Which ports should be open?
Only the ones you actively serve — typically 80 and 443 for web. Databases, SSH and admin interfaces should be restricted by source address rather than exposed to the internet.