Exercises: Setting up a home network

What is the network name or SSID? Explain why it is not a good idea for your home Wi-Fi name to include your surname or address, and suggest a good name for a family network.

What is Wi-Fi network encryption? Explain in your own words what happens to data travelling over an open network without a password and what risk that carries.

The figure shows the settings screen of a home router, with the encryption field still to be decided, as shown in the diagram.

Explain what each of the three settings on the screen is used for. Then answer: the encryption field is undecided; research which option you would choose between WEP, WPA2 and WPA3, and justify your choice.

True or false? Justify each answer: (a) the Wi-Fi name can be seen from outside the house; (b) hiding the network name makes it impossible to find and attack; (c) the password to enter the router settings should be different from the Wi-Fi password; (d) WPA2 is a type of Wi-Fi network encryption.

Explain what a "guest network" is and why it is a good idea to activate it when friends come over, instead of giving them the main Wi-Fi password.

The router has its own "administrator" password to access its settings. Explain who in your family should know it and why it is serious if it remains set to the factory default, which anyone can find online.

Even if your Wi-Fi has a password, any neighbour can see some data about your network: its name and encryption type. Explain what they cannot see without the password (what you type, your passwords, your photos) and why encryption makes the difference.

Rank these options from best to worst idea for home Wi-Fi and justify the order: leaving the network without a password "because I have nothing important", using the factory password on the sticker, using your name and birth year, using a long made-up phrase.

Your home Wi-Fi still uses the factory default password that came on the router, a sticker you showed to a visitor. Analyse whether it is advisable to change it, what features the new password should have, and where to keep it so you do not forget it without letting anyone see it.

A neighbour asks you for the "favour" of sharing your Wi-Fi for a few days, and you give them your main home password. Evaluate two risks of this decision and suggest a safer alternative that allows you to lend a hand without giving them access to your entire network (for example, a guest network).

Put the steps for securely connecting a new mobile phone to your home Wi-Fi in order, and explain why the step of checking the name is important: (a) choose your network from the list of available networks, (b) type in the password, (c) check that the network name is exactly yours and not a similar one, (d) verify that the connection works.

Your brother shares the home Wi-Fi password in the neighbourhood chat group "to help out". Analyse how many people that password could reach, what a stranger connected to your network could do (view devices, use up your bandwidth), and what you would do now to fix it.

The new mobile phone connects to the Wi-Fi without any problem, but the old smart light bulb does not appear on the list. A common cause is that the router has two "bands" (2.4 GHz and 5 GHz) and the light bulb only understands 2.4 GHz. Explain what it means for a router to have two bands and how you would check and resolve the issue in the settings.

Your family rents out a holiday cottage to travellers and wants to offer them Wi-Fi. Set up the network: name, password type (the same for all guests or a different one for each stay?), whether a separate guest network from yours would be needed, and what written instructions you would leave in the welcome folder.

The router application alerts: "security update available". Explain why the router also needs updates, what can happen if they are ignored for years, and how such an update is usually installed (from the application or the router's settings page).

Your mother uses the same password for Wi-Fi, email, and banking. Analyse the risk of reusing passwords if one of them is compromised, and suggest a simple system for having different passwords without forgetting them (phrases by category of service, a password manager, etc.).

Your grandmother tells you: "I've set my date of birth repeated twice (1204195512041955) as the Wi-Fi password. Since it's 16 digits long and nobody in the neighbourhood knows when I was born, it's completely invulnerable." Refute her reasoning by explaining two security weaknesses of her proposal, and design a method for her to generate a strong password that she can remember without writing it down, justifying why your method withstands both social engineering deduction and an automated attack.

At home, the Wi-Fi is running slowly and, upon logging into the router, you discover an unknown device downloading a large amount of data. Your brother suggests the fastest solution: "We click the disconnect button on the list, turn the router off for 10 seconds, and that's it." Refute why his idea is ineffective and design a four-step ordered action plan to resolve the intrusion definitively, justifying why the order in which you apply each action is critical.

Three students share a flat and have conflicting needs: Lucía handles confidential banking data from her job; Marcos plays online games and demands the lowest possible latency; and Sergio invites friends over almost daily who ask for the Wi-Fi password to watch videos. Design how you would organise the local network (wired connections vs. Wi-Fi, network segmentation, and access rules) to solve the security and performance problems of all three, justifying each technical decision.

Analyse the following audit report for a home router: SSID: "Familia_Perez_3B"; Encryption: "WEP"; Wi-Fi key: "perez2024"; Router admin password: "admin"; WPS button: "Permanently enabled"; Devices: 5 known and 2 unknown with high data usage. Detect the four most serious security flaws ranked from highest to lowest risk, justify what specific danger each one poses to the family, and describe the exact technical correction you would apply to the router to fix them.

In a café, the Wi-Fi password is written on a blackboard in plain view of everyone. Your friend connects and says: "Since the network has a password, the traffic is encrypted and it's impossible for anyone in the café to see what I'm doing on my phone." Analyse technically why his reasoning is flawed, explain what real risks he takes on by browsing that network, and justify three essential precautions you should take on your device if you need to connect there.

You suspect that a neighbour has been using your Wi-Fi connection without permission for weeks, but they only connect at odd hours and your family doesn't notice any slowness during the day. Design an investigation strategy using the router's tools (DHCP table, connection logs, and activity lights) to confirm their presence without alerting them, and explain what definitive configuration measures you would take to block their access even if they had found out your current password.

A small medical clinic has a single router and needs to provide service to: consultation computers containing patient records, doctors' mobile phones, and patients' devices in the waiting room. Design the complete network structure (wired or wireless distribution, subnet separation, and access policies), and technically justify how your design prevents a malicious patient in the waiting room from intercepting or accessing medical records.

Imagine tomorrow's headline: "The encryption used by most routers is no longer secure". Explain step by step what would happen to the data travelling over Wi-Fi networks, what manufacturers and network providers would do, and what you as a user should do until a solution arrives.