Check common service ports. Browser-based scanning has limitations due to CORS and security policies. For comprehensive port scanning, use a dedicated tool like nmap.
What is Port Scanner Tool?
Port Scanner checks which TCP ports are open on a target server. Ports are communication endpoints for network services - each service runs on a specific port (HTTP:80, HTTPS:443, SSH:22). Open ports indicate running services. This tool scans common service ports to identify accessible services, useful for security audits and service discovery.
How to Use
- Enter host name or IP address
- Select common ports to scan (SSH, HTTP, HTTPS, etc.)
- Add custom ports if needed (comma-separated)
- Click Scan Ports to begin scanning
- View results showing port status
- Identify open services for security assessment
Why Use This Tool?
Tips & Best Practices
- Open ports indicate running services
- HTTPS/443 open suggests web server active
- SSH/22 open means remote access enabled
- MySQL/3306 open may indicate database exposure
- Use nmap for comprehensive port scanning
- Browser limitations affect accuracy
Frequently Asked Questions
What ports are commonly scanned?
20 common ports: 20,21 FTP, 22 SSH, 23 Telnet, 25 SMTP, 53 DNS, 80 HTTP, 110 POP3, 143 IMAP, 443 HTTPS, 465 SMTPS, 993 IMAPS, 995 POP3S, 3306 MySQL, 3389 RDP, 5432 PostgreSQL, 5900 VNC, 6379 Redis, 8080 HTTP Proxy, 27017 MongoDB. Select relevant ports for your use case.
What are browser limitations for port scanning?
Browser CORS policies restrict cross-origin requests. Port scanning via browser uses HTTP requests instead of TCP SYN packets (traditional scanning). 'Likely Open' indicates HTTP response received. 'Unknown' means browser couldn't determine due to security restrictions. For accurate results, use server-side tools like nmap.
What does 'Likely Open (CORS)' mean?
HTTP request to the port returned a response (even CORS error). This indicates something is listening on that port - the service is running. CORS error means browser can't read response content, but connection was established, suggesting port is open.
How do I scan custom ports?
Enter port numbers in 'Custom Ports' field, comma-separated (e.g., 3000,5000,8000). Ports must be 1-65535. Custom ports are added to selected common ports. All selected ports are scanned when clicking 'Scan Ports'.
Why use this instead of nmap?
Browser-based scanning is quick, accessible, requires no installation. Useful for basic checks, service discovery, learning about ports. For security audits, production servers, comprehensive scans, use nmap (command-line) for accurate TCP/UDP scanning with detailed results.
What security implications do open ports have?
Open ports expose services to potential attacks. SSH (22) enables remote access - secure with key auth. Database ports (3306, 5432, 27017) shouldn't be public. RDP (3389) can be exploited - use VPN. Close unnecessary ports, firewall sensitive services, use non-standard ports for internal services.