A Beginner’s Guide to Building Cybersecurity Skills in 2025 – Network Security

In today’s digital age, cyber threats are everywhere hospitals, banks, schools, and even smart home devices are under constant attack. Cybersecurity isn’t just for experts anymore; it’s a must-know skill for anyone working in IT.

The Certified Network Security Practitioner (CNSP) certification is your first step into the world of cybersecurity. Whether you’re a student, an IT professional looking to switch careers, or just curious about how networks stay secure, this guide breaks everything down in simple, practical steps.

1. Why CNSP Matters in 2025

Cyberattacks are growing faster than ever—ransomware, data breaches, and phishing scams cost businesses billions each year. Companies need professionals who can protect their networks, and CNSP gives you the foundational skills to start.

Who is this for?

• Absolute beginners with no prior cybersecurity knowledge

• IT professionals wanting to specialize in security

• Students looking to enter the cybersecurity field

This guide assumes zero experience and teaches you everything step by step.

2. Understanding TCP/IP and the OSI Model

Before securing a network, you need to know how it works.

What is TCP/IP?

Think of TCP/IP as the internet’s “language.”

• TCP (Transmission Control Protocol) ensures data arrives correctly (like tracking a package).

• IP (Internet Protocol) handles routing (like the postal service).

The OSI Model – 7 Layers Explained

This model shows how data moves between devices:

Pro Tip: Remember the layers with: “Please Do Not Throw Sausage Pizza Away.”

3. IPv4 vs. IPv6 – What’s the Difference?

Every device needs an IP address to connect to a network.

IPv4 (Old but Still Used)

• Format: 192.168.1.1

• Only 4.3 billion addresses (we’ve run out!)

IPv6 (The Future)

• Format: 2001:0db8:85a3::8a2e:0370:7334

• 340 undecillion addresses (enough for every device on Earth)

Why IPv6 is better:
✔ More secure
✔ Faster routing
✔ No more NAT headaches

4. Networking Devices: Hubs, Switches, Routers

Not all devices are created equal.

Best Practice: Always use switches over hubs—they’re faster and more secure.

5. Network Discovery – Finding Devices

Before securing a network, you need to know what’s connected.

Common Tools & Protocols:

• Ping (ICMP): Checks if a device is online

• SNMP: Monitors network devices

• LLDP: Finds connected switches/routers

Why It Matters:

• Detects unauthorized devices

• Helps in troubleshooting

6. Network Mapping & Vulnerability Scanning

Nmap – The Hacker’s (and Defender’s) Best Friend

• Scans for open ports

• Identifies running services

• Detects security weaknesses

Example Command:

nmap -sV 192.168.1.1

(Scans a device and shows running services)

Wireshark  Seeing Network Traffic

• Captures live data packets

• Helps detect malware or suspicious activity

7. Cryptography How Encryption Works

3 Types of Encryption:

1. Symmetric (AES) – One key for both encryption & decryption

2. Asymmetric (RSA) – Public & private keys (used in HTTPS)

3. Hashing (SHA-256) – One-way encryption (for passwords)

Real-World Uses:

• VPNs (Secure remote access)

• SSL/TLS (Secure websites)

• Password storage (Hashed, not plaintext)

8. Active Directory & Authentication

What is Active Directory (AD)?

Microsoft’s system for managing users, permissions, and devices in a network.

Key Concepts:

• Domain Controller: The “brain” of AD

• Group Policy: Controls user permissions

• Least Privilege: Users get only the access they need

Security Best Practices:
✔ Enable Multi-Factor Authentication (MFA)
✔ Regularly audit user permissions
✔ Limit admin access

9. Malware & Social Engineering

Common Cyber Threats:

• Ransomware (Locks files until you pay)

• Phishing (Fake emails tricking users)

• Man-in-the-Middle (MITM) (Hacker intercepts data)

Social Engineering Hacking the Human

Instead of breaking systems, attackers trick people into:

• Clicking malicious links

• Sharing passwords

• Downloading infected files

How to Stay Safe:
❌ Never share passwords over email/phone
✅ Verify requests through another channel (call, in-person)

10. Must-Know Security Tools

Hands-On Exercise:
Try scanning your home network with Nmap to see connected devices.

11. What’s Next After CNSP?

CNSP is just the beginning. After mastering these basics, you can specialize in:

• Penetration Testing (Ethical hacking)

• Cloud Security (AWS, Azure)

• Incident Response (Handling cyberattacks)

Final Advice:
Cybersecurity is a lifelong learning journey. Stay curious, practice with labs, and keep up with new threats.

Resources & Next Steps

• Free Labs: Try Hack The Box

• Books: “Network Security for Dummies” (Beginner-friendly)

• Certifications: After CNSP, consider CEH, Security+, or CISSP