Networking Fundamentals
Objective: Understand how computers communicate over networks.
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.
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IP addresses (IPv4 and IPv6) : What they are, how subnetting works
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DHCP vs. static IP assignment
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DNS : How domain names resolve to IP addresses
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TCP vs. UDP : Connection-oriented vs. connectionless protocols
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Ports : What they are, common numbers: 22 (SSH), 53 (DNS), 80 (HTTP), 443 (HTTPS)
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The OSI model : All 7 layers, what each one does
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MAC addresses : What they are, where they live (Layer 2)
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Default gateways and routing basics
ip addr View network interfaces and IP addresses ip route View your routing table ping Test connectivity to another host traceroute See the path packets take to a destination dig Query DNS records (A, MX, NS, TXT) nslookup Simpler DNS lookup tool ss / netstat View active connections and listening ports curl Make HTTP requests from the terminal wget Download files from the web via terminal nmcli Manage NetworkManager from the command line - 1
Find your machine's IP address, subnet mask, default gateway, and DNS server using only CLI commands. Write them down.
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Assign a static IP address using nmcli or by editing Netplan config files. Verify it works.
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Diagram your home network: every device, every connection, IP addresses, the router, and the ISP handoff. Paper or any diagramming tool.
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Use dig to find the A record, MX record, and NS records for google.com. Explain what each one means in plain English.
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Use traceroute to trace the path to three different websites. Identify hop counts and where the latency spikes are.
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Temporarily change your DNS server to 1.1.1.1 (Cloudflare) or 8.8.8.8 (Google). Verify by resolving a domain.