Hands-on networking and security validation lab focused on understanding real traffic behavior and defensive controls.

🔐 Network Communication & Security Lab

🧭 Lab Architecture

                              Host-Only Network

+---------------------+        Network Traffic        +----------------------+
|     Kali Linux      |  <------------------------->  |     Ubuntu Server    |
|   (Test / Attacker) |                               |      (Target)        |
|                     |                               |                      |
| - Nmap Scanning     |                               | - SSH Service (22)   |
| - Netcat Testing    |                               | - Nginx Web (80)     |
| - Traffic Analysis  |                               | - UFW Firewall       |
+---------------------+                               +----------------------+

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📌 Overview

This project demonstrates practical networking fundamentals and basic host hardening in a controlled virtual lab environment.

The objective was to understand how network communication works at a technical level and how security controls affect traffic flow. The lab focuses on validating exposed services, analyzing TCP behavior, and implementing firewall policies with measurable before-and-after results.

This project is part of my hands-on learning journey while studying networking and cybersecurity concepts.

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🎯 Objectives

• Build a controlled lab environment using virtual machines
• Validate IP addressing and network connectivity
• Identify exposed services and listening ports
• Perform TCP and UDP network scanning
• Capture network traffic to observe TCP communication behavior
• Apply firewall hardening using UFW
• Verify security improvements through rescanning and logs
• Document methodology and findings professionally

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🧪 Lab Environment

Attacker Machine

• Kali Linux
• Tools used:
  • Nmap
  • Netcat
  • Curl

Target Machine

• Ubuntu Server
• Services:
  • OpenSSH
  • Nginx Web Server
• Security Tools:
  • UFW Firewall
  • tcpdump

Network Design

VirtualBox environment with:

• Host-only network (isolated lab communication)
• Optional NAT interface (for updates only)

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🧠 Methodology

1️⃣ Validate network configuration

• Check IP addressing
• Confirm routing
• Verify connectivity

2️⃣ Baseline Assessment

• Identify listening services
• Perform TCP and UDP scans
• Document exposed attack surface

3️⃣ Traffic Analysis

• Capture packets using tcpdump
• Observe TCP handshake behavior

4️⃣ Security Hardening

• Configure UFW firewall
• Apply default deny inbound policy
• Allow only required services

5️⃣ Verification

• Re-scan target
• Compare before/after results
• Analyze firewall logs

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📂 Project Structure

Network_Communication_Security_Lab/
│
├── README.md
├── scope.md
├── architecture.md
├── commands/
│ └── commands_used.md
├── scans/
│ ├── nmap_tcp_before.txt
│ ├── nmap_udp_before.txt
│ ├── nmap_tcp_after.txt
│ └── nmap_udp_after.txt
├── firewall/
│ ├── ufw_rules_after.txt
│ └── ufw_log_sample.txt
├── captures/
│ ├── tcpdump_handshake_http.txt
│ └── tcpdump_handshake_ssh.txt
└── screenshots/

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🔍 Key Findings

• TCP and UDP scanning provide different visibility into services
• TCP reliability can be observed through SYN/SYN-ACK/ACK sequences
• Host firewall configuration significantly reduces attack surface
• Proper documentation makes technical work reproducible and verifiable

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🧰 Skills Demonstrated

• Network configuration validation
• TCP/IP communication understanding
• Port and service analysis
• Network reconnaissance using Nmap
• Packet capture and analysis
• Firewall policy implementation
• Security documentation practices

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⚠️ Disclaimer

This project was conducted in a fully isolated lab environment for educational purposes only. No real systems or external networks were targeted.

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👤 Author

Wassim Abelghouch

Cybersecurity Student | Aspiring Security Engineer