In most small offices the network is whatever the internet company installed on day one: one router in a corner, the default Wi-Fi name, a password written on the wall, and everyone (staff, guests, the printer, the cameras) on the same network.
It works, until it doesn't: the far office has no signal, a visitor's infected phone sits next to the accounts PC, or nobody knows the router's admin password when the line goes down.
Here is a simple, safe setup that fits most offices of 5 to 30 people. The security points follow published advice from the US cyber agency CISA and the UK's NCSC, checked on 11 October 2026.
1. Change the router's admin password
The router has two passwords: the Wi-Fi password and the admin password that opens its settings. The admin one is often still the default printed on the sticker.
- Change it to a long, unique password.
- Save it in the company password manager, not on the wall.
2. Use WPA3, or at least WPA2 with AES
These are the security settings for your Wi-Fi.
- WPA3 is the current standard. The Wi-Fi Alliance requires it on new Wi-Fi certified devices.
- If some older devices can't connect, use WPA2 (AES). Never leave the network open or on old WEP or WPA.
3. Make a separate guest network
Visitors, personal phones and smart devices (TVs, cameras, smart plugs) go on a guest network. CISA's advice is that devices on the guest network should not be able to reach your other devices or the router's settings.
- Staff network: work PCs, the printer, the NAS.
- Guest network: everything else, with its own password that you can change often.
4. Turn on automatic updates
Router and access point makers fix security holes through firmware updates (the router's own software).
- Turn on automatic updates if the router has them.
- If not, check every three months.
- If the maker no longer sends updates for your model, plan to replace it.
5. Get coverage right
- One router in a corner rarely covers a whole office. Two or three access points, or a mesh system, give steady signal everywhere.
- Wire what doesn't move. Desktops, the printer, the NAS and the main PCs are faster and steadier on a cable.
- Wi-Fi 6 or newer handles many devices at once much better. Wi-Fi 7 certification started in January 2024, but Wi-Fi 6 is enough for most small offices today.
6. Small things that save big headaches
- A UPS (a battery backup) for the router and switch keeps the internet up through short power cuts.
- A second internet line from a different provider, if the business stops when the internet stops.
- A simple diagram: where the router is, which cable goes where, and who to call. Keep it with the passwords.
- Turn off WPS, the push-button connect feature. It is convenient but weak.
A quick check you can do today
- Can you open the router's settings yourself, right now?
- Is the Wi-Fi password the one on the sticker?
- Are guests on the same network as the accounts PC?
- When was the router's firmware last updated?
If you are unsure about any of these, start there.
In short: a private admin password, WPA3, a separate guest network, automatic updates and good coverage. None of it is expensive, and it removes the most common ways into a small office network.
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Sources: CISA Project Upskill, Module 5 · NCSC small organisations guide: protecting your devices · Wi-Fi Alliance: security · Wi-Fi Alliance introduces Wi-Fi CERTIFIED 7. Checked 11 October 2026.