🧪 DNS Lab 📌 Objective Understand DNS from a systems perpective ⚙️ Environment Virtualization: VirtualBox OS: ( 1 DNS Server VM + 1 Client VM) 🛠️ Lab Network Topology 🧩 Phase 1 — Direct DNS (No Cache) Client VM -> dnsmasq (192.168.10.10) Used for: Break #1 (Wrong DNS Server) Break #2 (Wrong DNS Record) 🧩 Phase 2 — Direct DNS (No Cache) Clint VM -> systemd-resolved (127.0.0.53) [CACHE] -> dnsmasq (192.168.10.10) [DNS SERVER] ...
🧪 Process Management & Resource Control Lab 📌 Objective Simulate and troubleshoot a real-world system slowdown caused by CPU saturation and memory exhaustion. ⚙️ Environment Virtualization: VirtualBox OS: Ubuntu Server 🛠️ Lab Setup Step 1 - Create CPU Load Script nano cpu_hog.sh chmod +x cpu_hog.sh Step 2 - Create Memory Load Script (Python) nano mem_hog.py chmod +x mem_hog.py 🚨 Incident Simulation Step 1 - Check the System Load Baseline uptime ...
🧪 DHCP Lab 📌 Objective Understand how DHCP works in real network environment and how to debug common failure scenarios using a structured top-to-bottom approach. ⚙️ Environment Virtualization: VirtualBox OS: Ubuntu Server (1 DHCP Server VM & 2 Client VMs) Network mode: Internal Network + NAT (enp0s3 ignored for DHCP lab) 🛠️ Network Setup Interfaces DHCP Server enp0s8 -> 192.168.10.10/24 (Lab network) enp0s3 -> NAT Clients enp0s8 -> DHCP assigned IPs enp0s3 -> NAT (not used) ⚙️ Network Configuration (Netplan) Both server and clients are configured using Netplan, which defines interface behavior before DHCP starts. ...
🧪 Linux Networking and Service Exposure Lab 📌 Objective This lab simulates real-world Linux networking issues and teaches how to troubleshoot: Service availability Port listening Firewall behavior (UFW) Binding (’localhost’ vs external access) Network-layer debugging ⚙️ Environment OS: Ubuntu (VM + Bridged Adapter) Service: Nginx Tools: ss, curl, ufw, systemctl Host machine for external testing (Powershell) 🟢 Stage 1 Verify service: systemctl status nginx Expected outcome: Active (running) Check listening ports: ...