TCP Port Checker
Test TCP connectivity to one or more host:port combinations. Attempts direct TCP connections to check if ports are open and measures connection latency.
Port Check Examples
Port Check Configuration
Common Ports
Understanding TCP Port Connectivity
Port States
- Open: Port accepts connections and responds
- Closed: Port actively refuses connections
- Filtered: Port blocked by firewall (appears as timeout)
- Timeout: No response within timeout period
Common Ports
- SSH (22): Secure remote access
- HTTP (80): Web traffic
- HTTPS (443): Secure web traffic
- SMTP (25/587): Email sending
Troubleshooting Tips
- Timeouts often indicate firewall blocking
- Connection refused means service is not running
- Check both client and server firewalls
- Verify service is listening on expected port