TCP Port Test
Check if a TCP port is open on any host. Enter an IP or hostname and port number; we attempt a connection and report open, closed, or filtered. Useful for firewall verification, service checks, and troubleshooting connectivity.
Test TCP Port
Enter host and port to check connectivity.
How to Use This Tool
Enter a hostname or IP address and a port number. We try to open a TCP connection from our server. If the connection succeeds, the port is open. If we get "connection refused," the port is closed. If we get no response before the timeout, we report filtered (usually a firewall dropping packets).
Why This Tool Matters
After changing firewall rules or moving a service to a new port, you need to confirm the port is reachable from the internet. This tool runs from our server, so it tests external reachability. It's different from testing locally — your machine might reach a port that the rest of the world cannot.
Use Cases
- Verify port 80 or 443 is open after configuring a web server
- Confirm SSH (22) or RDP (3389) is reachable through your firewall
- Check if email ports (25, 587, 993) are open for your mail server
- Test database ports (3306, 5432) after opening them for remote access
FAQs
What does TCP port test do?
It tries to open a TCP connection to the given host and port. If the connection succeeds, the port is open. If it fails or times out, the port is closed or filtered.
What ports should I test?
80 and 443 for web, 22 for SSH, 25/587/993 for email, 3306 for MySQL, 5432 for PostgreSQL. Test any port 1-65535 you need to verify.
Why does it say "filtered"?
Filtered means no response arrived before our timeout. A firewall or network device is likely dropping the connection silently.
Is this the same as a port scanner?
We test one port at a time. A full port scan would check many ports; use this for targeted checks on specific ports.
Can I test from my own network?
The test runs from our server. To test from your network, run "telnet host port" or use a local port checker.