Port check

Open, closed or filtered

• Open: the handshake completed, so a service is listening and reachable from the internet.
• Closed: the host answered with a refusal. It is up, but nothing listens on that port.
• Filtered: no answer before the timeout. A firewall is dropping the connection, or the host is down.

Pick a preset (web, mail, remote access, databases) or enter up to 20 ports of your own. For open ports MtrXTools waits briefly for the banner some services send first, such as SSH or SMTP, which shows what is actually running.

Common uses

• Confirm that a port forward or firewall rule works from outside your network.
• Find services exposed by mistake, such as a database (3306, 5432) or remote desktop (3389) open to the whole internet.
• Check a mail server answers on 25, 465 and 587.

Questions

Is it legal to check ports?

Checking a handful of ports on your own systems is routine. Only test hosts you own or are allowed to test; MtrXTools limits each run to 20 ports and never runs exploit checks.

The port is open on my network but filtered here. Why?

Your router or ISP may block incoming connections, you may be behind CGNAT, or the service may only listen on a local address.