networking

the internet vs. local network

think of it this way: your home network is like the hallways inside your house, only people living there can walk through them. The internet is the road outside, where billions of houses connected together.

When you stream a video, your device talks to your home network first, which then reaches out to the internet to fetch the video. Your neighbour cannot wander through your hallways, but you both share the same road.

  ┌─────────────────────────────────┐
  │       YOUR HOME NETWORK         │
  │                                 │
  │   [ PC ]  [ Phone ]  [ TV ]    │
  │      \        |        /        │
  │       └───[ Router ]───┘        │
  └───────────────┬─────────────────┘
                  │
            ══════╪══════
              THE INTERNET
            ══════╪══════
                  │
         [ Google, YouTube,
           Amazon, etc. ]
        

what is an ip address?

Every device on a network needs a unique address so that data gets delivered to the right place, just like a postal address tells the mail carrier which house to stop at.

An IP address is that address for your device. It is a set of numbers separated by dots.

The numbers are split into four groups. Each group can be an integer between 0 and 255. That gives enough unique combinations to address billions of devices.

  IP Address:   192  .  168  .   1   .  50
                 │       │       │      │
                 │       │       │      └── device number (which device)
                 │       │       └───────── subnet (which room)
                 └───────┴───────────────── network (which building)
        

what is a router?

A router is the traffic director of your network. It sits at the edge of your home network and decides whether data goes to another device on your home network, or out to the internet.

Your internet provider gives you one public IP address for your whole home. The router shares that one address across all your devices using a trick called NAT (Network Address Translation). From the internet's point of view, your entire household looks like a single device.

  INTERNET ───── [ Router ] ───── Home Devices
                     │
               One public IP          Many private IPs
               e.g. 76.14.23.101      e.g. 192.168.1.x
        

what is a switch?

A switch is a network splitter. It gives you more wired ports so you can plug in more devices. Where a router connects your home to the internet, a switch just connects devices to each other within your home network.

Routers usually have four wired ports built in. If you need to connect more wired devices, you plug a switch into the router and connect everything to the switch.

  [ Router ]
       │
  [ Switch ]          ← gives you more wired ports
   /   |   \
  /    |    \
PC   NAS   Printer
        

what is wi-fi?

Wi-Fi is just networking without the wires. Your router (or a separate device called an access point) broadcasts a radio signal. Your phone, laptop, or tablet picks up that signal and connects to your network the same way a wired cable would, just without the physical cable.

  [ Router / Access Point ]
           ')))
     (radio waves)
      /    |    \
  Phone  Laptop  Tablet
        

public vs. private ip addresses

There are two kinds of IP addresses and it is worth knowing the difference.

  YOUR HOME:                         INTERNET:
  private addresses                  public address
  (invisible outside)                (visible to everyone)

  [ PC ]       192.168.1.10  ─┐
  [ Phone ]    192.168.1.11  ─┤── [ Router ] ── 76.14.23.101 ──▶ internet
  [ TV ]       192.168.1.12  ─┘
        

what is dns?

Computers only understand numbers. When you type google.com into your browser, your computer has no idea where that is. It needs to translate that name into an IP address it can actually connect to.

That translation is done by a DNS server, think of it as the internet's phone book. You look up a name, it resolves the number.

  You type:  google.com
       │
       ▼
  [ DNS Server ]  ← "what's the IP for google.com?"
       │
       ▼
  142.250.80.46   ← "here you go"
       │
       ▼
  Your browser connects to that IP address
        

what is ethernet?

Ethernet is wired networking. You plug one end of a cable (called an Ethernet cable or RJ-45 cable) into your device and the other end into a router or switch.

Wired connections are almost always faster and more reliable than Wi-Fi. Radio signals can be disrupted by walls, other devices, or interference. A cable is a direct physical path. No interference, no guessing.

basic troubleshooting

Most internet problems at home fall into a small number of categories. Work through these steps in order before calling your provider.

1. step 01
   restart your router (and modem if separate).
   Unplug the power. Wait 30 seconds, long enough for the hardware to fully reset. Plug back in and wait 60-90 seconds for the connection to re-establish. This fixes the majority of home internet issues.
2. step 02
   check your cables.
   If using a wired connection, unplug and re-seat the Ethernet cable at both ends. Try a different cable if you have one. A loose or damaged cable causes intermittent connection problems that are easy to miss.
3. step 03
   verify wi-fi.
   Make sure you are connected to your network and not a neighbour's. Try forgetting the network on your device and reconnecting from scratch. Check that you are using the correct password.
4. step 04
   test with a different device.
   If your phone works but your PC doesn't (or vice versa), the problem is with that specific device, not the router. If nothing connects, the problem is likely the router or your internet service.
5. step 05
   run a ping test.
   Open a command prompt (Windows: search "cmd" in Start) and type the command below. If you get replies, your internet connection is working. If you see "request timed out," there is a connectivity problem.

glossary

a small index of the terms on this page.