Port Scanner

Port Scanner - Online Network Port Scanning Tool

A powerful port scanner tool for network security testing and diagnostics. Scan common ports, well-known services, or custom port ranges to identify open, closed, and filtered ports on any host. Essential for network administrators, security professionals, and penetration testers.

What is a Port Scanner?

A port scanner is a security tool that probes a server or host for open ports. It helps identify:

- Which network services are running
- Potential security vulnerabilities
- Firewall configurations
- Network connectivity issues

Port scanning is essential for:
- Network security auditing
- Penetration testing
- System administration
- Troubleshooting network issues

Port scanners work by sending packets to specific ports and analyzing the responses to determine if ports are open, closed, or filtered.

How to use this Port Scanner?

Using the Port Scanner:

1. Enter Target:
- Enter hostname (e.g., example.com)
- Or IP address (e.g., 192.168.1.1)

2. Choose Scan Mode:
- Common Ports: Scans 22 most common ports (HTTP, HTTPS, SSH, FTP, etc.)
- Well-Known Ports: Scans important well-known service ports
- Custom Ports: Specify your own ports (e.g., 80,443 or 1-1000)

3. Start Scan:
- Click 'Start Scan'
- Watch real-time progress
- Review results showing open/closed/filtered ports

4. Interpret Results:
- Open: Service is accessible
- Closed: Port is closed
- Filtered: Port may be behind firewall

IMPORTANT: Only scan hosts you own or have explicit permission to test. Unauthorized port scanning may be illegal.

What do Open, Closed, and Filtered ports mean?

Port Status Meanings:

OPEN:
- A service is actively listening on this port
- The port accepts connections
- Examples: Web server on port 80, SSH on port 22
- Security implication: Potential entry point

CLOSED:
- No service is listening on this port
- The port actively refuses connections
- The host is reachable but service is not running
- Security implication: Generally safe

FILTERED:
- Cannot determine if port is open or closed
- Usually blocked by firewall
- Packets are dropped without response
- Security implication: Good firewall practice

Note: Due to browser security restrictions, this tool may have limited accuracy compared to native tools like Nmap. Results should be verified with dedicated security tools.

What are Common Ports?

Common ports are frequently used network service ports:

Web Services:
- 80: HTTP (Websites)
- 443: HTTPS (Secure websites)
- 8080: HTTP Proxy/Alternative
- 8443: HTTPS Alternative

Email:
- 25: SMTP (Sending mail)
- 110: POP3 (Receiving mail)
- 143: IMAP (Mail access)
- 587: SMTP Submission
- 993: IMAPS (Secure IMAP)
- 995: POP3S (Secure POP3)

File Transfer:
- 20, 21: FTP (File transfer)
- 22: SSH/SFTP (Secure file transfer)

Databases:
- 3306: MySQL
- 5432: PostgreSQL
- 27017: MongoDB
- 6379: Redis

Remote Access:
- 22: SSH (Secure shell)
- 23: Telnet (Insecure - avoid)
- 3389: RDP (Remote Desktop)
- 5900: VNC (Remote desktop)

Other:
- 53: DNS (Domain name system)

These ports are commonly targeted by attackers, so they should be secured and monitored.

Is Port Scanning Legal?

Legal Considerations:

LEGAL USE:
- Scanning your own systems and networks
- Authorized security testing with written permission
- Testing systems you administer
- Penetration testing with proper authorization
- Security research on your infrastructure

ILLEGAL USE:
- Scanning systems without permission
- Unauthorized network reconnaissance
- Attempting to find vulnerabilities to exploit
- Commercial scanning without consent

Best Practices:
1. Always get written authorization
2. Only scan systems you own or have permission to test
3. Follow responsible disclosure practices
4. Document your authorization
5. Comply with local laws and regulations

Unauthorized port scanning can be considered:
- Computer intrusion
- Unauthorized access attempt
- Network trespassing

Penalties may include fines and imprisonment. Always ensure you have proper authorization before scanning any network or system.

Browser vs Native Port Scanners

Limitations of Browser-Based Port Scanners:

Browser Limitations:
- CORS (Cross-Origin Resource Sharing) restrictions
- Cannot directly open TCP connections
- Limited to HTTP/HTTPS protocols
- Slower than native tools
- Less accurate results
- Cannot perform stealth scans
- Limited port range (avoid overwhelming browser)

Advantages:
- No installation required
- Cross-platform compatibility
- Quick basic checks
- User-friendly interface
- Good for initial reconnaissance

Native Tools (Nmap, etc.):
- Direct TCP/UDP connection control
- Advanced scan techniques (SYN, ACK, etc.)
- Stealth scanning capabilities
- OS detection
- Service version detection
- Script scanning (NSE)
- Much faster
- More accurate

Recommendation:
Use this browser tool for:
- Quick checks
- Basic diagnostics
- Learning about ports
- Initial reconnaissance

Use native tools (Nmap, Masscan) for:
- Professional security testing
- Comprehensive network audits
- Penetration testing
- Production security scanning

Key Features

• Scan common ports (22 most used)
• Scan well-known service ports
• Custom port ranges and lists
• Real-time scan progress
• Identify open, closed, and filtered ports
• Service name identification
• Port statistics and summary
• Support for domains and IP addresses
• IPv4 support
• Stop scan anytime
• Fast sequential scanning
• No installation required
• Free to use
• Mobile-friendly design
• Dark mode support