Port Scanner

Check if common ports are open on any host or IP address

What is Port Scanner?

The Port Scanner is a free online tool that checks whether common ports are open or closed on any host or IP address. It is used by developers and network engineers to verify firewall rules, check service availability, and troubleshoot connectivity issues without installing any software.

Why Use DevBench Port Scanner?

DevBench Port Scanner runs entirely in your browser — your data never leaves your device. No sign-up, no limits, no watermarks, completely free forever.

How to Use Port Scanner

  1. Enter a domain name or IP address in the input field
  2. Click "Scan Common Ports" to check all standard ports
  3. Or enter a custom port number and click "Scan Port"
  4. View which ports are open (green) or closed (grey)
  5. Use results to verify firewall and service configuration

Examples

  • Scan a server to check if port 80 (HTTP) is open
  • Verify port 443 (HTTPS) is accessible on your domain
  • Check if port 22 (SSH) is open on a VPS
  • Verify port 3306 (MySQL) is not exposed publicly
  • Check if port 6379 (Redis) is accidentally open

Use Cases

  • Verifying firewall rules are correctly configured
  • Checking which services are exposed on a server
  • Troubleshooting connection refused errors
  • Verifying database ports are not publicly accessible
  • Checking web server port availability
  • Auditing server security posture
  • Verifying VPN and proxy port configuration

Frequently Asked Questions

What ports are scanned by default?

Common ports including 21 (FTP), 22 (SSH), 80 (HTTP), 443 (HTTPS), 3306 (MySQL), 5432 (PostgreSQL), 6379 (Redis), 27017 (MongoDB), and more.

Is port scanning legal?

Only scan servers you own or have permission to scan. Unauthorized port scanning may be illegal.

Why does a port show closed when the service is running?

Firewalls may block the scan. A closed result means the port did not respond, not necessarily that the service is down.

Can I scan private IP addresses?

No, private IPs are not accessible from the internet. Only public IPs and domains can be scanned.

How accurate are the results?

Results reflect whether the port responded to a TCP connection attempt. Firewalls may cause false negatives.