Port Checker
Free online port checker and reference tool. Check if common ports are open, generate Nmap/Masscan scan commands, and browse well-known port/service mappings. No signup required.
Live TCP Port Scanner
Run real server-side TCP handshake probes to detect exposed endpoints, service latencies, and security risks.
Scanner Standby
Exposing closed database links or vulnerable RDP channels is risky. Choose ports above and hit "Start Scan" to probe!
Target Handshake Diagnostics
How to Use Port Checker
Open the Port Checker tool on toollabs.in.
Enter the domain, IP address, or network parameter you want to analyze.
The tool generates the appropriate command or queries the relevant DNS/network service.
Review the results including technical details, response data, and suggested next steps for troubleshooting.
Why Use Port Checker?
Port Checker on toollabs.in is designed for quick network diagnostics. Diagnostic requests are processed statelessly in-memory and queries are never logged, tracked, or stored on our servers.
Designed for developers, system administrators, and security practitioners, Port Checker streamlines common inspection, diagnostic, and syntax generation workflows directly in your browser.
Built with modern web standards and responsive layouts, Port Checker runs smoothly across desktop and mobile devices without requiring extra plugins or software installation.
100% Free
No subscriptions, no paywalls, no hidden costs
Privacy First
All processing happens in your browser
Lightning Fast
No server latency, instant results
No Signup
Start using immediately, no account needed
Frequently Asked Questions
How can I check if a port is open?▼
You can use tools like Nmap (nmap -p <port> <host>) or Telnet (telnet <host> <port>) to check if a specific port is open. This tool generates the correct commands and provides a reference of common port/service mappings.
What are the most common ports to check?▼
Common ports include 80 (HTTP), 443 (HTTPS), 22 (SSH), 21 (FTP), 25 (SMTP), 3306 (MySQL), 5432 (PostgreSQL), 27017 (MongoDB), 6379 (Redis), 8080 (HTTP-alt), and 8443 (HTTPS-alt).
Can I scan my own network?▼
Yes, you can scan systems you own or have permission to test. Use Nmap for local network scans and always ensure you have authorization before scanning external systems.
How does the online port check work?▼
When you click 'Check Port', your browser sends a request to our stateless backend proxy (/api/port-checker), which attempts a TCP socket connection against the target host and port with a 3-second timeout. It returns whether the connection succeeded, timed out, or was refused. The tool also generates copyable CLI commands (Nmap, Netcat, PowerShell) for running scans directly from your local terminal.
Use Cases
Firewall Verification
Check which ports are exposed through your firewall configuration
Service Deployment
Verify that a service is listening on the expected port after deployment
Security Auditing
Identify unnecessary open ports that could be attack vectors
Network Troubleshooting
Diagnose connectivity issues by checking if specific ports are reachable
Examples
Check Single Port
Input:
Host: example.com, Port: 443
Output:
nmap -p 443 example.com nc -zv example.com 443 telnet example.com 443
Common Ports Quick Scan
Input:
Host: scanme.org
Output:
nmap -p 22,80,443,8080,3306,5432 scanme.org
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