Port Scanner

A port scanner is a network tool that tests which ports are open on a target host. This browser-based scanner uses HTTP/HTTPS requests for web ports and WebSocket connections for other ports to determine if services are running and accessible.

This tool can scan common ports (21, 22, 25, 53, 80, 443, etc.), custom port lists, or port ranges. It works best with HTTP/HTTPS ports (80, 443) and can test other ports using WebSocket connections, though results may vary due to browser security limitations.

Browser-based port scanning has limitations compared to traditional network scanners. It works very well for HTTP/HTTPS ports but may show false negatives for other ports due to browser security policies. Results should be interpreted considering these constraints.

Open: The port is accessible and responding. Closed: The port is not accepting connections. Filtered: The port may be protected by a firewall or the connection was rejected. Timeout: The connection attempt timed out, indicating possible filtering or network issues.

You can scan any publicly accessible hostname or IP address. However, browser security policies may prevent scanning localhost, private networks, or certain protected domains. The tool works best with public web services and domains.

Common ports include standard services like HTTP (80), HTTPS (443), SSH (22), FTP (21), SMTP (25), and others. Scanning these helps identify running services, verify configurations, and assess security posture of web applications and servers.

Scan time depends on the number of ports and network conditions. Common port scans (17 ports) typically take 30-60 seconds. Custom ranges may take longer. The tool scans in batches to balance speed with browser performance.

Port scanning your own servers and websites is generally legal. However, scanning systems you don't own without permission may violate terms of service or local laws. Always ensure you have proper authorization before scanning external systems.

Filtered status typically indicates the port is protected by a firewall, the service is rate-limiting connections, or network policies are blocking the scan. This is common for security-sensitive ports and properly configured network defenses.

This tool can be part of a security assessment for web applications, but it should not be the only tool used. Due to browser limitations, it's best used for checking web service availability and basic connectivity rather than comprehensive security auditing.

If expected services appear closed, check: network connectivity, firewall settings, service configuration, and whether the service is actually running. You may also try scanning from different networks to rule out local network restrictions.

Traditional scanners like Nmap have more capabilities and accuracy since they operate at the network level. This browser-based tool is convenient for quick web service checks but has limitations due to browser security policies. Use it for basic connectivity testing and web service verification.