Open Port Checker
Test whether a TCP port on a public IP address or domain can accept an incoming connection. Useful for troubleshooting web servers, SSH, remote desktop, game servers, and port forwarding.
Check a TCP Port
Enter a public hostname, IPv4 address, or IPv6 address and one TCP port.
Port result
Common TCP Ports
Choose a common service below or enter any TCP port from 1 to 65535.
| Port | Service | Typical use | Test |
|---|---|---|---|
| 21 | FTP | File Transfer Protocol control connection | |
| 22 | SSH | Secure remote shell and SFTP | |
| 25 | SMTP | Mail server transport | |
| 53 | DNS | Domain Name System (TCP can be used) | |
| 80 | HTTP | Unencrypted web traffic | |
| 443 | HTTPS | Encrypted web traffic | |
| 3306 | MySQL | MySQL database connections | |
| 3389 | RDP | Microsoft Remote Desktop |
What the Port Checker Actually Tests
The result is based on a real TCP connection attempt from the Fast IP Checking server.
Open
If the remote system completes a TCP connection on the selected port, the tool reports the port as open. This generally means a service is listening and reachable from the internet.
Closed or Filtered
If a connection cannot be established, the service may be closed, a firewall may be filtering the connection, the target may be unreachable, or the hosting network may block that outbound port.
Public Targets Only
Private, loopback, link-local, multicast, and other non-public address ranges are blocked. Domain names are resolved first and the resolved public address is validated before the connection is attempted.
One Port at a Time
This utility is intentionally designed for targeted diagnostics, not bulk scanning. Each request tests a single public target and a single TCP port.
Port Checker Questions
Quick answers about TCP port testing and interpreting the result.
An open TCP port means the target accepted a connection on that port at the time of the test. It usually indicates that a service is listening, but it does not by itself prove that the service is secure or correctly configured.
The server did not establish a TCP connection before the test ended. The port may be closed, filtered by a firewall, blocked by the hosting network, or temporarily unreachable.
Yes, if you own or administer it. Use your public IP address, make sure the service is listening, and confirm that any required router port-forwarding and firewall rules are configured correctly.
No. Fast IP Checking tests one host and one TCP port per request. This keeps the tool focused on legitimate diagnostics rather than bulk scanning.
No. This version checks TCP connectivity only. UDP testing behaves differently and cannot be reliably represented by the same open/closed connection test.
The application does not create a persistent database of submitted host-and-port checks. Normal hosting and security infrastructure may still process standard request logs as part of operating the website.