Networking

Objective The goal of this lab is to design and implement a basic DMZ (Demilitarized Zone) network using Linux virtual machines, understand routing between network segments, and apply nftables as a stateful firewall. Network Topology LAN (User Network) DMZ (Service Network) 192.168.10.0/24 192.168.20.0/24 __________________ _____________________ Client VM Server VM 192.168.10.101 192.168.20.10 | | | | ________ Firewall VM ___________ (Router + Firewall) VM & Routing Configuration Client VM sudo netplan try sudo netplan apply Firewall VM (Core Router) ...

Objective Lab Environment Client VM 1 - 192.168.10.101 Client VM 2 - 192.168.10.102 Server VM - 192.168.10.10 Server Setup Step 1 - Run web server python3 -m http.server 8080 ss -tln | grep :8080 Step 2 - Base firewall configuration sudo nft add table inet filter sudo nft add chain inet filter input \ '{ type filter hook input priority 0; policy drop; }' sudo nft add rule inet filter input iif lo accept sudo nft add rule inet filter input ct state established,related accept ...

🧪 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. ...

🧪 Basic Network Setup & Connectivity Lab 📌 Objective Understand how IP addressing, subnetting, and basic connectivity work in a controlled virtual environment. ⚙️ Environment Virtualization: VirtualBox OS: Ubuntu Server (2 VMs) Network mode: Internal Network + NAT VMs VM IP Address Role VM1 192.168.10.10/24 Client VM2 192.168.10.20/24 Server 🛠️ Setup Step 1 - Create Virtual Machines Create two Linux virtual machines: server_01 server_02 Recommended specs: 1 CPU 1-2 GB RAM 10+ GB disk Step 2 - Configure Network Both VMs must use the same Internal Network This ensures both machines are on the same isolated Layer 2 network. ...