Path 9 · Networking
Networking
How devices, routers, addresses, DNS and websites work together, and how to diagnose network problems with simple tools.
By the end you will be able to
- Describe how a home network and the internet fit together.
- Read IP addresses and explain DNS and DHCP.
- Explain what happens when a web page loads.
- Diagnose common network problems step by step.
Before you start
- Recommended first: Internet and Communication
Module 33: Networking fundamentals
What a network is, what each box in a home network does, and how data is cut into packets and sent by agreed rules.
- What is a network?
A network is a group of devices that can send data to each other. Learn the difference between a LAN and the wider internet, what clients and servers are, and how a typical home network is laid out.
25 min · beginner
- Routers, switches, modems, access points, Ethernet and Wi-Fi
Learn what a modem, router, switch and access point each do, how cables and Wi-Fi compare, and what a network interface is. You will be able to read the back of a router and find your own connections in Settings.
25 min · beginner · Ubuntu/Linux · Windows
- Packets, protocols, bandwidth and latency
See how any message is cut into small packets, sent by different routes and put back together, why devices need shared rules called protocols, and why speed has two parts: bandwidth and latency.
25 min · elementary
Module 34: IP addressing and DNS
How devices are numbered with IP addresses, how they get them automatically, how names are turned into numbers, and how ports, TCP, UDP and ping fit in.
- IP addresses: IPv4, IPv6, public and private
Learn how to read an IPv4 address, why your phone and the website you visit have very different kinds of address, what IPv6 is for, and how a MAC address differs from an IP address.
30 min · elementary
- DHCP, DNS and the default gateway
Find out how a device gets its address automatically (DHCP), how a name like example.org becomes a number (DNS), and how the default gateway is the door out of your home network.
30 min · elementary · Ubuntu/Linux · Windows
- Ports, TCP and UDP, ping and traceroute
Understand how one address serves many programs through ports, why TCP and UDP exist, and how ping and traceroute test a connection, so you can read a ping result with confidence.
30 min · elementary · Ubuntu/Linux · Windows
Module 35: The web and HTTP
How a web address is built, how browsers and servers talk using HTTP and HTTPS, and how hosting, CDNs, cookies and sessions make the web work.
- Domains, URLs, HTTP and HTTPS
Take a web address apart piece by piece, follow the request and response a browser exchanges with a server, and understand what the padlock of HTTPS does and does not promise.
30 min · elementary
- Web servers, hosting, CDNs, cookies and sessions
See where websites actually live, why big sites copy themselves to many places, and how cookies and sessions let a site remember you although the web itself has no memory.
30 min · elementary
Module 36: Network diagnostics
Where to find network settings on Ubuntu and Windows, which built-in tools to use, and a calm step-by-step method for finding out why a network is not working.
- Network settings and diagnostic tools
Find your network settings on Ubuntu and Windows, and use ping, address listings, name lookups, route tracing and the routing table to see what your computer knows about the network.
30 min · intermediate · Ubuntu/Linux · Windows
- Wi-Fi signal, router restarts and firewalls: diagnosing step by step
Judge Wi-Fi signal problems, restart a router in the right order, understand what a firewall does, and follow a decision tree that finds the broken link in a home network.
30 min · intermediate