What is a port scanner and why do I need it?

A port scanner is a security tool that checks which network ports are open on a server. Open ports can be entry points for hackers, so scanning helps identify potential vulnerabilities before attackers do.

Which ports are commonly targeted by hackers?

High-risk ports include 3306 (MySQL), 3389 (RDP), 22 (SSH), 21 (FTP), and 1433 (SQL Server). These services, when exposed to the internet, are frequent targets for brute-force attacks.

How do I close an open port?

To close a port, configure your firewall to block incoming connections, stop the service using that port, or bind it to localhost only. Always backup configurations before making changes.

Is it legal to scan ports?

Port scanning is legal only on systems you own or have explicit permission to test. Unauthorized scanning of other systems may violate computer fraud laws and terms of service agreements.

What do the scan results mean?

Green indicates an open port accepting connections, while red means the port is closed or filtered. Open ports should only exist for services you intentionally expose to the internet.

🔍 Online Port Scanner Tool

📚 Complete Guide & FAQ

🎯 Why Use This Port Scanner?

Exposed ports are the #1 entry point for cyber attacks. This tool helps you identify which services are accessible from the internet, preventing data breaches, unauthorized access, and server compromises. Regular port scanning is essential for maintaining robust security posture.

📋 How to Use This Tool

Step 1: Enter Target
Input the IP address or domain name of the server you want to scan. Only scan systems you own or have permission to test.

Step 2: Add Custom Ports (Optional)
Besides the 37 commonly vulnerable ports we check by default, you can add up to 5 custom port numbers (1-65535) to scan specific services.

Step 3: Analyze Results
Green/open ports are accepting connections from the internet. Click "Open" to verify the service. Red/closed ports are properly secured or filtered.

❓ Frequently Asked Questions

What ports does this scanner check by default?
We scan 37 high-risk ports including database services (MySQL 3306, PostgreSQL 5432), remote access (SSH 22, RDP 3389), web services (HTTP 80, HTTPS 443), and mail servers (SMTP 25, POP3 110). These are commonly exploited by attackers.

I found open ports - am I at risk?
Open ports themselves aren't vulnerabilities, but unnecessary open ports increase attack surface. Evaluate each open port: Is this service needed externally? Is it properly secured with strong authentication? Can it be restricted to specific IPs?

How often should I scan my servers?
Perform scans monthly as part of regular security audits, immediately after server configuration changes, and whenever deploying new services. Set up automated monitoring for critical infrastructure.

What's the difference between closed and filtered ports?
Closed ports actively refuse connections, while filtered ports don't respond at all (usually due to firewall rules). Both are secure states - filtered is slightly better as it reveals less information to potential attackers.

Can attackers use this tool against me?
Port scanning is a double-edged sword. While attackers do scan for vulnerabilities, regular self-scanning helps you find and fix issues first. Think of it as checking your doors and windows before leaving home.

Which services should never be exposed?
Database servers (MySQL, PostgreSQL, MongoDB), development tools (Docker, Kubernetes APIs), and internal services should always be firewalled. Use VPN or SSH tunnels for remote access instead of direct exposure.

Why can\'t I scan private IP addresses?
This tool blocks private/local IP ranges (192.168.x.x, 10.x.x.x, 172.16-31.x.x) for security reasons. These addresses aren\'t accessible from the internet anyway. Use local tools for internal network scanning.

What should I do after finding vulnerabilities?
Document all findings, prioritize by risk level, implement firewall rules for unnecessary services, update/patch exposed services, enable strong authentication, monitor logs for suspicious activity, and consider hiring security professionals for critical systems.

💬 Need help securing your infrastructure? Visit our Support Center for expert guidance and advanced security recommendations.