How this test works
One selected Globalping probe attempts TCP connections to one public host and one port. This is not a port scanner.
TCP CONNECTIVITY
TCP Port Check
Test whether a single public TCP port is reachable.
Remote synthetic measurement
Test completedResults are ready.
How to read the result
A failed connection can mean a closed service, a firewall, or a network timeout. It does not prove the host itself is offline.
Frequently asked questions
What is the most common port to check?
443 (HTTPS), followed by 80 (HTTP), 22 (SSH) and 3389 (Remote Desktop). Testing 443 is the standard "is the web server up" check.
Can I scan all 65535 ports?
Not with this tool, and not casually. It checks one TCP port per run and is not a scanner; sweeping a host's full port range without authorization is against the terms of most networks and can be illegal. Use scanning tools only on systems you own or are authorized to test.
Why does my port show closed even though my service is running?
The service may be bound to a private address, listening on a different port, or blocked by a firewall on the host, the router or the provider. An external "closed" means the outside world can't reach it. Check binding addresses first, then firewall rules, then forwarding.
What is port forwarding?
A router setting that forwards connections arriving at your public IP on a given port to a device inside your network. It's required for most self-hosted services to be reachable from the internet.
What is the difference between filtered and closed?
Closed means the host answered and refused; usually nothing listens there. Filtered means no answer at all, usually a firewall dropping the packets, but it could also mean the host or the path is down.
Learn how tcp port check works
Read the guide How to check if a port is open in 2026: remote and local tests, what open, closed and filtered mean, and the most common TCP ports.