Cyber Security Network Mapping & Port Scanning

Welcome to The Coding College, your trusted source for learning the fundamentals of cyber security. In this post, we will delve into Network Mapping and Port Scanning—two crucial techniques used in both cyber defense and penetration testing.

What is Network Mapping?

Network Mapping involves identifying the devices, systems, and topology of a network. It provides a visual representation or detailed report of how devices are connected and communicate within a network.

Key Objectives of Network Mapping:

  1. Inventory Management: Understand the devices and systems on a network.
  2. Vulnerability Identification: Detect outdated devices or systems with weak configurations.
  3. Incident Response: Quickly identify affected areas during a security breach.

Tools for Network Mapping

  1. Nmap (Network Mapper): A powerful open-source tool for scanning and mapping networks.
  2. SolarWinds Network Topology Mapper: Automates the creation of network maps.
  3. Microsoft Visio: Useful for manually creating network diagrams.
  4. Angry IP Scanner: Lightweight and fast for scanning smaller networks.

What is Port Scanning?

Port Scanning is a technique used to discover open ports on a device or network. Ports act as gateways for communication, and identifying open ports helps assess which services are running and their potential vulnerabilities.

Types of Ports

  1. Well-Known Ports (0-1023): Reserved for common services like HTTP (80) and HTTPS (443).
  2. Registered Ports (1024-49151): Used by software and applications.
  3. Dynamic/Private Ports (49152-65535): Temporary ports often assigned by operating systems.

Common Port Scanning Techniques

  1. TCP Connect Scan
  • Establishes a full TCP connection to test if the port is open.
  • Pro: Reliable results.
  • Con: Easily detectable.
  1. SYN Scan (Half-Open Scan)
  • Sends SYN packets without completing the handshake.
  • Pro: Faster and stealthier.
  • Con: May be blocked by firewalls.
  1. UDP Scan
  • Sends UDP packets to check open ports.
  • Pro: Useful for identifying DNS, DHCP, and other UDP services.
  • Con: Slower and more prone to false positives.
  1. Xmas Scan
  • Sends packets with all flags set to identify operating systems and open ports.
  • Pro: Effective against older systems.
  • Con: Rarely used due to modern defenses.
  1. Ping Sweep
  • Checks for active devices on a network by sending ICMP packets.
  • Pro: Quick and useful for network discovery.
  • Con: Often blocked by modern firewalls.

Tools for Port Scanning

  1. Nmap: The go-to tool for port scanning, offering multiple scanning methods.
  2. Zenmap: A graphical interface for Nmap, ideal for beginners.
  3. Netcat (nc): Lightweight and versatile for scanning and communication.
  4. Masscan: Capable of scanning entire networks at high speed.

Security Implications of Network Mapping and Port Scanning

Both techniques are used by attackers and defenders:

For Cyber Defenders:

  • Proactive Defense: Identify and close unnecessary ports to reduce the attack surface.
  • Compliance: Ensure network configurations meet security standards.
  • Incident Response: Quickly analyze potential entry points during a breach.

For Attackers:

  • Reconnaissance: Gather information on a network’s structure and vulnerabilities.
  • Target Identification: Pinpoint systems or services with exploitable weaknesses.

How to Secure Your Network Against Malicious Scanning

  1. Enable Firewalls
  • Block unauthorized port scans using firewalls or intrusion prevention systems (IPS).
  1. Use Port Knocking
  • Configure services to open ports only after receiving a specific sequence of connection attempts.
  1. Monitor Network Traffic
  • Use tools like Wireshark or Snort to detect scanning attempts.
  1. Disable Unnecessary Services
  • Close unused ports and remove unnecessary services to minimize vulnerabilities.
  1. Implement Rate Limiting
  • Limit the number of requests to slow down and discourage scanning attempts.

Legal and Ethical Considerations

While network mapping and port scanning are essential for penetration testing, performing these actions without permission is illegal in most jurisdictions. Always obtain explicit consent before scanning networks.

Why Learn Network Mapping & Port Scanning?

These skills are foundational in cyber security, helping professionals to:

  • Understand network infrastructure.
  • Identify and mitigate vulnerabilities.
  • Prepare for certifications like CEH (Certified Ethical Hacker) and CompTIA Security+.

At The Coding College, we provide in-depth tutorials to equip you with these practical skills.

Final Thoughts

Network mapping and port scanning are double-edged swords in the realm of cyber security. When used ethically, they empower defenders to strengthen systems and thwart attacks.

Explore more about ethical hacking, cyber security, and network defense at The Coding College.

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