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.
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 to be the fastest, most privacy-respecting option available online. Unlike many alternatives, our tool processes everything directly in your browser — your data never touches our servers.
Whether you're a developer debugging an API, a student learning network concepts, or a professional working with sensitive data, Port Checker provides a reliable, zero-cost solution with no registration required.
Built with modern web standards and optimized for performance, the tool loads instantly and works across all devices — desktop, tablet, and mobile. It even works offline after the initial page load.
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.
Why can't I check ports directly from the browser?▼
Web browsers cannot make arbitrary TCP connections due to security restrictions. Port scanning requires native tools like Nmap or Masscan that can create raw network sockets. This tool helps you generate the right commands.
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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