Who is on my Wi-Fi? How to find unknown devices on your network

Why it is worth checking

A typical home today has twenty or thirty devices on the Wi-Fi: phones, laptops, the TV, the printer, a few smart plugs, the robot vacuum, a doorbell. A small office has more. Most of them you set up once and forgot. So when the network feels slow, or you simply wonder whether a neighbour still has the password you gave them two years ago, the honest answer is usually “I don’t know who is on it”.

Finding out takes five minutes, and it answers more than the security question: it is also how you find the old tablet still downloading updates, the camera nobody remembers installing, or the printer that changed address and broke everyone’s printing.

Start from the router’s own list

Every router keeps a list of the devices it has handed an address to. It is the most complete source, because every device has to ask the router to join.

1. Open the router’s page in a browser — usually 192.168.1.1 or 192.168.0.1, or the address printed on the label underneath it.
2. Log in with the admin password (also on the label, if nobody ever changed it — which is worth fixing while you are there).
3. Look for a page called Connected devices, DHCP clients, Device list or Home network.

You get, for each device, an IP address, a MAC address (a hardware identifier) and often a name. The catch: many names are empty or cryptic — android-3f2a9c, ESP_1B2C3D, Unknown — and the list rarely tells you what the device actually is.

Scan the network from a phone or PC

A network scanner goes the other way: it knocks on every address on your network and records who answers. It finds devices the router’s list labels badly, and it can ask each one about itself:

• the name it announces (many devices tell the network what they are);
• the manufacturer, from the first half of the MAC address, which is assigned to the company that made the network chip;
• the services it offers — a printer answers on printing ports, a camera on video ports, a PC on file-sharing ports.

Put together, 192.168.1.37 · Espressif · port 80 open stops being a mystery: Espressif makes the Wi-Fi chip inside most smart plugs and bulbs.

One thing a scanner cannot always do is read MAC addresses. Since Android 10 apps are no longer allowed to see them, and phones and laptops now often use a random MAC per network for privacy. So “unknown manufacturer” on its own is not a warning sign — it is usually a modern phone protecting its owner.

How to tell what each device is

Work through the list with these clues, from the strongest to the weakest:

Clue	What it tells you
A name it announces	Living-room TV, HP LaserJet, MacBook-Air — usually right.
Manufacturer	Apple, Samsung, Amazon, TP-Link, Espressif, Tuya… narrows it down to a family of devices.
Open services	A printer, a camera, a NAS, a Windows PC all have recognisable ports.
When it appears	A device that comes and goes at 8 am and 6 pm is probably someone’s phone.
Elimination	Switch a device off and scan again: whatever vanished from the list was it.

The last one is the slowest and the most reliable. For a stubborn unknown, unplugging things one at a time always gets you there.

Signs that a device does not belong

Most “unknown” devices turn out to be your own. Be more suspicious when:

• a device appears that matches nothing you own, with a known manufacturer and a fixed (not random) MAC;
• it shows up at night or when everyone is out;
• it offers services you would not expect on a home network — remote desktop, an open database, file sharing — on a device you cannot place;
• the number of devices keeps growing without anyone buying anything.

What to do if you find an intruder

1. Change the Wi-Fi password, and use WPA2 or WPA3 — never WEP, never an open network. Every device you own will need the new password; the intruder will not have it.
2. Change the router’s admin password if it is still the default printed on the label.
3. Turn off WPS, the “push the button to connect” feature: it has known weaknesses and is rarely needed.
4. Put guests and smart devices on the guest network, if the router has one, so a visitor’s phone or a cheap camera never sits next to your PC.
5. Keep the router’s firmware up to date, from its admin page or the manufacturer’s app.

Blocking a single MAC address in the router feels satisfying but is weak on its own: a MAC can be changed in seconds. The password is what keeps people out.

Doing it with NetBlade

NetBlade for Android does the scanning and the detective work in one place, without an account:

• the LAN scanner lists every device that answers, with its name, manufacturer, latency and open ports, and marks the ones it has never seen before as NEW;
• devices that announce themselves (TVs, printers, Apple devices, smart speakers) are named from what they publish on the network, so a missing MAC address does not leave them anonymous;
• where Android hides MAC addresses, NetBlade can read them from the router over SNMP, if the router supports it;
• you can name, tag and pick an icon for each device, so the next scan reads Marco's phone instead of an address;
• with background monitoring switched on for a network, NetBlade notifies you when a new device joins it. Android decides when background checks actually run, so the alert can come a little late — it is a safety net, not an alarm.

Scan once, name everything you recognise, and from then on anything new stands out on its own.

← All articles NetBlade for Android →