PHASE 05Intermediate3 weeks

Networking Fundamentals

Objective: Understand how computers communicate over networks.

The Mission

Every device you touch in IT is connected to a network. Networking is the backbone of IT; everything runs on it: email, web, cloud, security, VoIP, IoT. If you don't understand networking, you don't understand IT.

This isn't theory class. You're going to configure, test, and troubleshoot real network connections on your machine.

Concepts to understand

  • IP addresses (IPv4 and IPv6): What they are, how subnetting works

  • DHCP vs. static IP assignment

  • DNS: How domain names resolve to IP addresses

  • TCP vs. UDP: Connection-oriented vs. connectionless protocols

  • Ports: What they are, common numbers: 22 (SSH), 53 (DNS), 80 (HTTP), 443 (HTTPS)

  • The OSI model: All 7 layers, what each one does

  • MAC addresses: What they are, where they live (Layer 2)

  • Default gateways and routing basics

Networking commands
ip addrView network interfaces and IP addresses
ip routeView your routing table
pingTest connectivity to another host
tracerouteSee the path packets take to a destination
digQuery DNS records (A, MX, NS, TXT)
nslookupSimpler DNS lookup tool
ss / netstatView active connections and listening ports
curlMake HTTP requests from the terminal
wgetDownload files from the web via terminal
nmcliManage NetworkManager from the command line
The Challenge6 tasks
  1. 1

    Find your machine's IP address, subnet mask, default gateway, and DNS server using only CLI commands. Write them down.

  2. 2

    Assign a static IP address using nmcli or by editing Netplan config files. Verify it works.

  3. 3

    Diagram your home network: every device, every connection, IP addresses, the router, and the ISP handoff. Paper or any diagramming tool.

  4. 4

    Use dig to find the A record, MX record, and NS records for google.com. Explain what each one means in plain English.

  5. 5

    Use traceroute to trace the path to three different websites. Identify hop counts and where the latency spikes are.

  6. 6

    Temporarily change your DNS server to 1.1.1.1 (Cloudflare) or 8.8.8.8 (Google). Verify by resolving a domain.

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