How to See Who Uses Your WiFi and Block Intruders

Your wireless network has uninvited visitors

Have you noticed your home internet suddenly slowing down with no obvious changes in usage? Or spotted a strange device listed in your router’s panel with no idea where it came from? These are classic signs that someone may be using your Wi-Fi without permission. It’s not paranoia: it’s a real problem, and the solution is more within reach than you’d think.

In this guide, you’ll learn to identify which devices are connected to your network, recognize those that shouldn’t be there, and block them permanently. You don’t need to be an IT technician. With access to your router’s panel and about fifteen minutes, you can set everything in order.

What happens when someone invades your WiFi

When a neighbor or anyone from outside accesses your network without permission, they share bandwidth (the total data capacity your internet plan offers) with all your devices. It’s like sharing a water pipe: the more faucets open, the less pressure at each one.

The problem goes beyond slowness. Whoever is on your network can, depending on their technical knowledge level, intercept unencrypted traffic, access shared devices like printers and external hard drives, and even use your connection for illegal activities, which can fall back on the account holder. In 2026, with homes full of IoT devices (Internet of Things, including smart TVs, cameras, lights, and home appliances), the attack surface is much larger than it was ten years ago.

How to see all devices connected to your router

Via the router’s administrative panel

Every router has an administration interface accessible through a web browser. The default address is usually 192.168.0.1 or 192.168.1.1, but this varies by manufacturer. You’ll find this information printed on the label of the device itself.

Open your browser and type the router’s IP address in the address bar.
Log in with the administrator username and password (if you’ve never changed it, check the device label or manual).
Look for a section with names like Connected Devices, DHCP Clients, Network Map, or Connected Devices (in English, if the firmware wasn’t translated).
You’ll see a list with each device’s name (hostname), the IP address assigned to it, and the MAC address (a unique physical identifier for each network card, like a fingerprint of the device).

Take note or screenshot this list. Your next step is to identify each item.

Via the manufacturer’s app

More modern routers, such as TP-Link Deco, Asus ZenWiFi, and Intelbras Action lines, offer mobile apps that display the device list more clearly and, in some models, with photos and automatic categories. If your router has an app, use it: it’s usually more intuitive than the web panel.

Using third-party apps on your computer or phone

If the router panel is confusing or the list appears incomplete, there are free apps that scan your local network and return all devices found. The most popular ones are:

Fing (available for Android and iOS, free): shows name, manufacturer, IP, and MAC of each device found.
Advanced IP Scanner (Windows, free): popular solution for computer use, with list export.
Angry IP Scanner (Windows, macOS, Linux, free): more technical, preferred by those with some network knowledge.

These apps work by sending small data packets across the network and waiting for responses from each active device. It’s a passive and harmless process.

How to identify unknown devices in the list

Seeing a list with names like “android-4f3a”, “ESP32-ABCD”, or simply a MAC address with no name at all can be disconcerting. Here’s how to decode it:

Check the manufacturer by MAC address: the first six characters of the MAC address identify the network card manufacturer. You can look up this prefix in public databases like the IEEE (Institute of Electrical and Electronics Engineers) database, using tools like Fing, which does this automatically.
Turn devices off one by one: with the list open, turn your devices off Wi-Fi (phones, tablets, TVs, consoles) and observe which disappear from the list. Whatever remains after you’ve identified all your devices is suspicious.
Pay attention to generic names: cheap IoT devices often appear with names like “baidu_…” or obscure Chinese manufacturers. These could be your own devices or something external.

How to block an intruding device

MAC address blocking on the router

The most direct method is the MAC filter (also called MAC access control). You instruct the router to only accept connections from MAC addresses you’ve pre-approved, or to block specific addresses.

Access the router’s administrative panel (same path as before).
Look for MAC Filter, Access Control, or MAC Filtering.
Add the intruding device’s MAC address to the block list (blacklist mode), or configure it for whitelist mode, where only your approved devices can connect.
Save and restart the router if necessary.

The whitelist mode is more secure, but requires you to register all your devices at once. It’s a time investment worth making on home networks with few fixed devices.

Important limitation: a user with technical knowledge can spoof their device’s MAC address (a technique called MAC spoofing), bypassing this filter. For casual intruders, like a neighbor trying to use your internet for free, MAC blocking works well. Against someone with malicious intent and technical knowledge, you need to go further.

Password change and security protocol

If you suspect an invasion, the most effective and immediate measure is to change your Wi-Fi password and ensure that your network’s security protocol is set to WPA3 (the newest and most secure standard, released by the Wi-Fi Alliance) or, if your router doesn’t support it, at least WPA2-AES.

Avoid WEP and WPA (older versions) which are vulnerable to known attacks.
Use a password with at least 16 characters, mixing letters, numbers, and symbols.
After changing the password, all devices will be disconnected and need to reconnect with the new credentials. Intruders are locked out.

Guest network for visits and IoT devices

Create a guest network on your router. Most modern models support this. It functions as a parallel network, isolated from your main network, where connected devices can’t see other devices in your home. Use this network for:

Giving internet access to visitors without exposing your devices.
Connecting IoT devices (cameras, smart TVs, lights), which often have weak security and can be attack vectors if compromised.

Routers with parental controls and advanced device management

If you want more refined control, routers with advanced firmware make device management much easier. Some options available in Brazil in 2026:

TP-Link Archer and Deco: the TP-Link Tether app lets you see and block devices with just a few taps. The Deco line, with mesh routers (a system of multiple access points forming a unified network), is sold nationally and has Anatel approval.
Asus ZenWiFi and RT-series: the ASUSWRT interface is known for its wealth of options, including security analysis via AiProtection (developed in partnership with Trend Micro, according to the manufacturer). Available in Brazil with local warranty from authorized retailers.
Intelbras Action: Brazilian brand with Portuguese support, guaranteed Anatel approval, and wide distribution. Simpler firmware, but sufficient for home use.
Motorola, Multilaser: budget alternatives available in major retailers, with basic panel and dedicated app.

Check the technical sheet of your chosen model to see if it supports WPA3, guest network, and device control via app, as these features vary even within the same product line.

Common problems and how to solve them

I can’t access the router’s panel

Make sure you’re connected to your router’s Wi-Fi network (or via cable). Open Command Prompt (Windows) or Terminal (macOS/Linux) and type ipconfig (Windows) or ifconfig (Mac/Linux) to find the default gateway, which is your router’s IP. Use that address in your browser.

I forgot the router’s administrator password

This is different from your Wi-Fi password. If it’s never been changed, the default is on the device label. If it was changed and you don’t remember it, the only way is a factory reset, usually done by pressing the button on the back of the router for 10 to 15 seconds. This erases all settings and you start from scratch.

The blocked device keeps appearing

Some routers take a few minutes to apply the MAC filter. Restart the router after saving settings. If the problem persists, check if your router’s firmware is updated, as bugs in this function have been reported and fixed in popular model updates.

I have many devices and can’t identify them all

Use Fing on your phone with automatic manufacturer identification. Disable random MAC on your own devices: modern iPhones and Android phones use random MACs by default for privacy on public networks, which can hinder recognition on your own home network. In your phone’s Wi-Fi settings, locate your home network and disable the random MAC address option for it.

Frequently asked questions about home Wi-Fi security

Can my neighbor really use my Wi-Fi without me noticing?

Yes, if the password is weak or if they got access to it at some point. Networks with WEP passwords, for example, can be broken in minutes with publicly available tools. WPA2 networks with simple passwords are also vulnerable to dictionary attacks, where the attacker tests common passwords automatically.

Does changing the Wi-Fi password resolve it permanently?

For the vast majority of cases, yes. A long and random password in WPA2-AES or WPA3 makes unauthorized access practically impossible for regular users. Combine this with periodic monitoring of your device list for more peace of mind.

Is MAC filtering sufficient as the only protection?

No. As explained, MAC spoofing allows you to bypass it. MAC filtering works best as an additional layer of security alongside a good password, not as a replacement for it.

Should I leave WPS activated on my router?

WPS (Wi-Fi Protected Setup) is a function that makes device connection easier without typing a password, usually via button or PIN. The problem is that the PIN version has known vulnerabilities. The general security recommendation is to disable WPS in your router’s panel unless you use it regularly and know what you’re doing.

Keep the habit of checking your network

Checking connected devices doesn’t need to be an obsessive weekly task, but a review every month or two is enough to catch any unauthorized access early. If you just got a new router or switched providers, take the opportunity to configure everything correctly from the start: strong password, WPA3 enabled, WPS disabled, and a separate guest network for IoT and visitors.

Anyone who wants to deepen their control over their own home technology will notice that this kind of attention is worth more than any new gadget. Speaking of smart technology choices, if you’re thinking about changing your phone at the same time, this guide on mid-range phones up to 2000 reais can help you make a well-founded decision. Digital security starts with the devices you use and the network through which they communicate.