Signs someone else is using your Wi-Fi
- Internet feels slower at odd hours
- Data usage on your ISP bill is higher than it should be
- Random device names you don't recognise show up in app notifications
- Your downloads throttle when you aren't streaming
Any of these are worth a 5-minute check. Here's how.
Step 1: log in to your router
Open a browser, type 192.168.1.1 or 192.168.0.1 (try both), press Enter. Login page appears. Username/password is usually admin / admin or printed on a sticker on the router itself.
If you've never changed it, that's your first action item after this exercise — change that password immediately.
Step 2: find the connected-clients list
Look for a menu named one of these (every manufacturer uses a different term):
- "Connected Devices"
- "DHCP Client List"
- "Attached Devices"
- "Device List"
- "Client List"
You'll see a table. Each row is one connected device, showing:
- Device name (often recognisable — "iPhone-Shivendra", "LG-TV", "Amazon-Echo")
- MAC address (12 hex chars)
- IP address (192.168.x.x)
- Sometimes a connection type (Wi-Fi vs Ethernet)
Step 3: account for every device
Walk through the list. Identify each:
- Your phone, your family's phones
- Every laptop and desktop
- Your smart TV, streaming stick
- Smart bulbs, Alexa / Google speakers, security cameras
- Printers
- The Wi-Fi kettle you forgot about
Anything left over that you can't account for is a potential intruder.
Step 4: verify with a MAC lookup
Not sure what a device is? Copy its MAC address (e.g. B4:5D:50:AA:BB:CC) and paste into https://macvendors.com. The first three bytes identify the manufacturer. "Apple, Inc." is probably your iPhone. "Xiaomi Communications" might be your robot vacuum. "Unknown" or "Private" on a device you don't own is a red flag.
Step 5: block and rotate
If you find something genuinely unauthorised:
- Change your Wi-Fi password right now. Make it long (20+ chars, a passphrase). All your devices will disconnect; reconnect each with the new password.
- Enable WPA3 if your router supports it (most routers from 2019+ do). WPA2 is now crackable with enough time. WPA3 is not.
- Turn on MAC filtering if you want overkill — whitelist only your known devices. Annoying to manage but effective.
- Rotate the router admin password too, if you still have the default.
Bonus: the Fing app
For an ongoing monitoring setup, install Fing on your phone (free). It scans your LAN and notifies when a new device joins. Easier than logging into the router every time.
Takeaway
Most "Wi-Fi intruders" turn out to be forgotten IoT devices. But if there's an actual unknown client, rotating your password is a 2-minute fix. A strong passphrase + WPA3 keeps opportunistic neighbours out permanently.