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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 minintermediateUbuntu/LinuxWindowsPractical task needs a laptop or desktop

Marking a lesson as read does not prove you can do it. Skills count as demonstrated when you pass the quiz (not yet) and complete the practical tasks (not yet).

By the end of this lesson you will be able to

  • Open the network settings on Ubuntu 24.04 and Windows 11 and read the address details.
  • List your addresses with `ip addr` or `ipconfig` and pick out the ones that matter.
  • Look up a name with `resolvectl query` or `nslookup` and say what the answer shows.
  • Trace a route with `tracepath` or `tracert` and read the hops.
  • Inspect your routing table and find the default route.

You have met the ideas: addresses, gateway, DNS, ping. This lesson turns them into practice. Your computer has built-in tools that show exactly what it knows about the network. Using them is like a doctor taking your temperature before guessing: a few readings turn a vague complaint such as 'the internet is bad' into a precise finding such as 'I have an address but cannot reach the gateway'.

Start close, move outward

A good diagnosis checks things in order, from your own device out to the wider internet. If an early check fails, later ones will fail too, and you have found where to look. The tools in this lesson match the steps of the ladder.

Diagram

Each check reaches one step further from your own computer.

  1. Step 1: SettingsJoined? Address?
  2. Step 2: Ping gatewayReach the router?
  3. Step 3: Trace routeWhere does it stop?
  4. Step 4: Look up a nameDoes DNS answer?
  5. Step 5: Open a siteEverything together
Each check reaches one step further from your own computer.
Read this figure as text

A flow of five checks from your own settings out to a website by name.

Step 1, Settings: am I joined to the network, and do I have an address that does not start with 169.254? Step 2, Ping gateway: can I reach my router, the door of my own network? Step 3, Trace route: where along the path to a site does the answer slow or stop? Step 4, Look up a name: does DNS turn a name into an address? Step 5, Open a site: does everything work together in the browser? The first step that fails shows where to look.

Network settings in the interface

Open the network settings

Menu names can differ slightly between releases. The ideas are the same.

On Ubuntu 24.04

  1. Step 1: Open Settings

    Press the Super key (the Windows key), type Settings and press Enter.

    You should see: The Settings window opens with a list of sections on the left.

  2. Step 2: Choose Wi-Fi or Network

    Click Wi-Fi (or Network for a cable). Find the connected network in the list.

    You should see: The connected network shows a tick or the word Connected.

  3. Step 3: Open the details

    Click the small gear (cog) beside the connected network, then open the Details tab.

    You should see: You see Signal Strength, Link speed, IPv4 Address, Hardware Address, Default Route and DNS.

Simulated interface: not a real screenshot

A simulated settings window showing the details that matter. Real windows differ by system and release.

Wi-Fi details (simulated)

Signal strength: Excellent

IPv4 Address: 192.168.1.20

Hardware Address: a4:5e:60:12:34:56

Default Route: 192.168.1.1

DNS: 192.168.1.1

  1. Marker 1: Radio link quality
  2. Marker 2: Your address (not 169.254)
  3. Marker 3: Your gateway
  4. Marker 4: Your DNS server
A simulated settings window showing the details that matter. Real windows differ by system and release.
Read this figure as text

A simulated settings window listing signal strength, IPv4 address, hardware address, default route and DNS.

A simulated settings window titled Wi-Fi details with rows: Signal strength, Excellent (marker 1: how strong the radio link is); IPv4 Address, 192.168.1.20 (marker 2: your address, which should not start with 169.254); Hardware Address, a4:5e:60:12:34:56 (the MAC address); Default Route, 192.168.1.1 (marker 3: your gateway); DNS, 192.168.1.1 (marker 4: the name server). All values are made up.

Listing your addresses

Show addresses

ip addr lists every network interface and the addresses it holds. The interface called lo is the loopback: your computer talking to itself at 127.0.0.1. Your real connection has a name such as wlp2s0 (Wi-Fi) or enp3s0 (cable). Look for the line starting inet. The /24 after the address is the subnet mask in short form: it means 255.255.255.0.

Terminal (Linux) · you can run this on your own computer
ip addr
List interfaces and their addresses (read-only)
Simulated interface: not a real screenshot

A simulated ip addr output; values are made up.

Terminal (simulated output)
  1. Marker 1: Command: list addresses
  2. Marker 2: Loopback: the computer talking to itself
  3. Marker 3: Your Wi-Fi interface, state UP
  4. Marker 4: Your address and mask (/24)
A simulated ip addr output; values are made up.
Read this figure as text

A simulated terminal showing ip addr output with the loopback and Wi-Fi interfaces.

A simulated terminal. Marker 1 is the command ip addr. The first entry, lo, is the loopback with the address 127.0.0.1/8 (marker 2: the computer talking to itself). The second entry, wlp2s0, is the Wi-Fi interface and its state is UP (marker 3). Its link/ether line gives the MAC address a4:5e:60:12:34:56. Its inet line gives 192.168.1.20/24, which is your private address with a mask of 255.255.255.0 (marker 4). The word dynamic shows that it came from DHCP. All values are made up.

Looking up names

To check DNS directly, ask for a name's address. If the answer comes back, DNS works and the problem lies elsewhere. If it fails, you have found the fault.

Look up a name

The tool dig is popular but is not installed on Ubuntu by default, so we use the built-in alternative.

resolvectl query example.org asks the system's own resolver for the address of example.org and says which interface and which method answered. It is part of Ubuntu 24.04 and only reads information.

Terminal (Linux) · you can run this on your own computer
resolvectl query example.org
Ask the system resolver for an address
Text
example.org: 198.51.100.40                     -- link: wlp2s0

-- Information acquired via protocol DNS in 21.4ms.
Simulated output with a made-up address; yours will differ

Tracing and routing

Tracing shows the hops on the way to a destination, as you saw in the previous lesson. The routing table is your computer's own list of directions: which gateway handles which destinations. It nearly always has two kinds of lines: one for your own subnet (reach it directly) and one default line for everything else (send to the gateway).

Trace a route and read the routing table

tracepath example.org is included with Ubuntu and shows each hop with its delay. ip route prints the routing table.

Terminal (Linux) · you can run this on your own computer
tracepath example.org
ip route
Trace the route, then show the routing table (read-only)
Text
default via 192.168.1.1 dev wlp2s0 proto dhcp metric 600
192.168.1.0/24 dev wlp2s0 proto kernel scope link src 192.168.1.20
Simulated routing table; values are made up

The first line says: for everything not listed elsewhere, use the gateway 192.168.1.1. The second says: addresses from 192.168.1.0 to 192.168.1.255 are directly reachable on the Wi-Fi interface.

Summary of the tools
QuestionUbuntuWindows
What is my address?ip addripconfig
Can I reach my router?ping -c 4 192.168.1.1ping 192.168.1.1
Does DNS answer?resolvectl query example.orgnslookup example.org
Where does the path stop?tracepath example.orgtracert example.org
Where are my directions?ip routeroute print

Common mistakes

  • ✖ Instead of: Running commands from a website or chat that you do not understand.

    ✔ Do this: Run only commands you have read and understood. Prefer the read-only tools in this lesson.

  • ✖ Instead of: Pasting full ipconfig or ip addr output into a public forum.

    ✔ Do this: It contains your MAC address and local addresses. Share only the lines needed, or replace the numbers.

  • ✖ Instead of: Blaming DNS or the provider as soon as a page will not open.

    ✔ Do this: Work through the ladder: address, gateway, name lookup, then the website. The first failure shows the area.

If something goes wrong

ping or tracepath says 'command not found'.
Check the spelling and that you are in a Terminal, not a text editor. These tools come with Ubuntu 24.04 and Windows 11. If one is missing, do not install software from a random website; note the exact message and ask someone you trust.
On Windows, route print shows a very long list.
Look only at the IPv4 Route Table and the line starting 0.0.0.0. Ignore the IPv6 part for now.
nslookup prints 'Server: UnKnown' before the answer.
It only means your DNS server has no reverse name. The answer below is still valid.

Key terms

Routing table
A list inside a device that says which way to send data for each destination.
Traceroute
A tool that lists the routers a packet passes through on its way to a destination.

Practise it for real

Reading is not the same as being able to do it. Complete these on your own computer, then tick only what you have actually done. These ticks are your own honest record: nothing checks them for you.

Guided exerciseNeeds a laptop or desktop

Write your own network report

On your real computer, collect: your IPv4 address and mask, your default gateway, your DNS server, the result of pinging your gateway (loss and average time), and the result of looking up example.org. Write them in a short table on paper or in a document. Keep the report private.

You have succeeded when:
Independent challenge

Challenge: what do these results say?

A neighbour sends you three results. (a) Her address is 169.254.9.4. (b) Her address is 192.168.1.20 and a ping to her gateway gets 4 of 4 replies, but nslookup example.org says 'DNS request timed out'. (c) Her ping to the gateway gets 0 of 4 replies. For each, write the most likely area of the fault and the next check you would ask her to do.

You have succeeded when:

Knowledge check

6 questions. You need 80% to pass. Mistakes here are part of learning, and you can retry as often as you like.

  1. Question 1.Match each question to the tool that answers it on Windows.
  2. Question 2.In inet 192.168.1.20/24, what does /24 stand for?
  3. Question 3.Commands such as ip route add are safe to try, because the worst result is a typing error.
  4. Question 4.Put these checks in a sensible order.
    1. Look up a name
    2. Ping the default gateway
    3. Open a website by name
    4. Check the address in Settings
  5. Question 5.Kamau's laptop has the address 192.168.1.20 and pings the gateway with 0% loss, but resolvectl query example.org fails.What is the most likely area of the fault?
  6. Question 6.On a routing table, what does the default route tell the computer?

Summary

  • Check close first and work outwards: settings, gateway ping, name lookup, website.
  • ip addr and ipconfig show your address; ip route and route print show your directions.
  • resolvectl query and nslookup test DNS; tracepath and tracert show where a path slows or stops.
  • Use the tools to read, not to change, and share outputs carefully.

Checklist: can you do these?

Marking a lesson as read does not prove you can do it. Skills count as demonstrated when you pass the quiz (not yet) and complete the practical tasks (not yet).

Related lessons

References and further reading

Official sources for details that can change between versions.

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