Are strangers using your Wi-Fi? 7 ways to check connected devices and block access

Have you noticed your internet has become slower than usual? Are pages taking longer to load, are videos lagging, and are online games lagging? One possible reason is... foreign devices, connected to your Wi-Fi. Other people's devices not only steal traffic but can also pose a security threat: through router vulnerabilities, hackers can intercept passwords, banking data, or infect the network with viruses.

According to data Kaspersky, more than 30% of home networks have been the target of unauthorized access at least once. And often, it's not the hackers who are to blame, but neighbourswho accidentally connected to an open network or guessed a simple password. In this article, we'll look at how identify all connected users, even if they disguise themselves as legitimate devices, and reliably protect your Wi-Fi from outsiders.

1. Checking via the router's web interface: a universal method

The most reliable way is to go to the router's control panel. It displays a complete list of devices, including their MAC addresses, IP address, and even model (if the router supports this feature). The instructions are suitable for most brands: TP-Link, ASUS, Keenetic, MikroTik and others.

To open the web interface:

• 🌐 Enter in the address bar of your browser 192.168.0.1 or 192.168.1.1 (the exact address is indicated on the router sticker).
• 🔑 Enter your login and password (by default it is often admin/admin or admin/empty).
• 📊 Find the section DHCP, Local area network, Wireless or Connected devices (the name depends on the model).

In the table, you'll see all active connections. Please note:

• 📱 Unknown device names (For example, Android-1234 or iPhone-abcdef, which are not in your arsenal).
• 🕒 Connection time: If the device is active at night when everyone is sleeping, it is suspicious.
• 📡 Connection type: wireless (Wi-Fi) or by cable (Ethernet).

⚠️ Note: Some routers (eg. Zyxel Keenetic) hide the MAC addresses of guest devices. In this case, check the section Guest network separately.

2. Using mobile apps: quick diagnostics

If you don't want to mess with your router settings, use specialized apps. They scan your network and display all connected devices, including their manufacturer (by MAC address). Popular utilities:

• 📱 Fing (Android/iOS) - identifies devices, checks ports, and even searches for vulnerabilities.
• 🛡️ WiFi Guard (Android) - Compares current connections with your "whitelist".
• 🔍 Network Analyzer (Android/iOS) - shows IP, MAC and even approximate location of devices.

How to use (using example) Fing):

1. Download the app and connect to your Wi-Fi network.
2. Click Scan — after 10–30 seconds a list of devices will appear.
3. Check unknown gadgets: the application will tell you their manufacturer (for example, Xiaomi, Samsung or Unknown).

The advantage of apps is that they work even if you don't have access to the router (for example, on a guest network). However, Not all utilities recognize spoofing. (MAC address spoofing), which is used by experienced hackers.

3. Windows Command Prompt: For Advanced Users

If you prefer to work without third-party programs, check the connected devices via command lineThis method will show all IP addresses on your local network, including those connected via cable.

Instructions:

1. Click Win + R, enter cmd and press Enter.
2. Enter the command:

   arp -a

   It will output a table of IP and MAC addresses mapping.

3. Compare the list with your devices. Unknown MAC addresses can be checked using services like MAC Vendors (enter the address into the search engine).

Example of command output:

Interface: 192.168.1.100 --- 0x12
Internet Address Physical Address Type
192.168.1.1 aa-bb-cc-dd-ee-ff dynamic
192.168.1.101 11-22-33-44-55-66 dynamic

⚠️ Attention: Team arp -a shows all devices on the local network, including those connected via cable. If you have smart TVs, printers, or IP cameras, their MAC addresses will also be displayed.

4. Traffic analysis: who is consuming your internet?

Unusual traffic patterns often occur with third-party devices: downloading torrents, playing online games, or streaming videos outside of normal business hours. You can check this using:

• 📊 Built-in router statistics (chapter Traffic, Monitoring or Bandwidth).
• 🖥️ PC programs: GlassWire, NetBalancer (show how much traffic each device consumes).
• 📱 Mobile applications: Network Monitor (Android) or Data Usage (iOS).

Signs of an unauthorized connection:

On routers ASUS And Keenetic there is a built-in traffic analyzer by devices. For example, in Keenetic go to Statistics → Traffic and see who consumes the most data.

How to distinguish legitimate traffic from third-party traffic?

If you have smart speakers (eg. Yandex Station or Amazon Echo), they can consume data even in the background for updates or voice commands. Check them manually or disable them for diagnostic purposes.

5. MAC Address Check: Identifying "Invisible" Guests

Experienced hackers can change the names of devices (for example, call their smartphone iPhone-Mom), But MAC address Changing this is more difficult. Each network adapter is assigned a unique MAC address, which can be used to identify the manufacturer.

How to check:

1. Collect the MAC addresses of all your devices (find them in the network settings or via the command ipconfig /all in Windows).
2. Compare them with the list from the router or app Fing.
3. Check unknown MAC addresses through databases like MAC Vendors Lookup - they will show the chip manufacturer (for example, Broadcom or Qualcomm).

Example of MAC address decoding:

• 2C:54:91:88:C9:E3 → Apple (iPhone/iPad/MacBook).
• 78:31:C1:BE:98:FA → Xiaomi (smartphone or smart device).
• 00:0A:EB:XX:XX:XX → ASUSTek Computer (router or PC).

⚠️ Warning: MAC addresses can be spoofed (MAC-spoofing), but this requires specialized knowledge. If you see a suspicious address from a well-known manufacturer (for example, Apple, but you don’t have devices of this brand), this is a reason to be wary.

Collect MAC addresses for all your devices | Compare them with the list in your router | Check unknown MAC addresses through the database | Check the manufacturer (doesn't match your devices?) | Block suspicious addresses in your router settings -->

6. Guest network and router vulnerabilities: how to close loopholes

Often strangers connect not to the main network, but to guest, if it is poorly protected. Check:

• 🔓 Is the guest network open without a password (in routers) TP-Link And D-Link it is sometimes enabled by default).
• 🔄 Does the guest network password match the main network password (this is dangerous!).
• 🕳️ Are there any known vulnerabilities in the router (check on the manufacturer's website or through a service) RouterCheck).

How to block access:

1. Disable the guest network if you are not using it (Settings → Guest Network → Disable).
2. Set a complex password (at least 12 characters with numbers and special characters).
3. Update your router firmware to the latest version (in System → Software Update).

For example, in routers Keenetic The guest network is configured in the section Home Network → Segments → Guest NetworkMake sure there is a check mark there. Isolate guests from the main network.

7. Additional security measures: how to prevent hacking

Detected a foreign device? Little Snitch (macOS) will show all outgoing connections.

If your suspicions are confirmed, follow the algorithm:

1. 🔄 Change your Wi-Fi password to complex (for example, k7#pL9!vQ2$mN5).
2. 🔒 Enable WPA3 (if the router supports it) or at least WPA2-PSK (V Settings → Wireless → Security Type).
3. 🚫 Block MAC addresses unknown devices in the router (MAC filtering).
4. 🔄 Reboot your router - This will reset all active connections.

For maximum protection, please set up MAC address whitelist (Allow only trusted devices to connect). This feature is available in most routers and is called MAC Filter or Access Control.

FAQ: Frequently asked questions about third-party connections

Is it possible to find out who exactly connected to my Wi-Fi?

It is impossible to identify a person precisely, but it is possible to find out:

• 📱 Device type (smartphone, PC, tablet) by MAC address.
• 🌍 Manufacturer (For example, Samsung, Xiaomi).
• 📡 Location (approximately, if the device is connected via Wi-Fi and you use specialized applications like Fing).

To identify a specific person, you will need the help of your provider or law enforcement agencies (if we are talking about hacking).

What should I do if a third-party device connects again after changing the password?

This is a sign that:

• 🔑 The password has been stolen again (for example, through phishing or eavesdropping).
• 🕳️ The router has a vulnerability that allows authorization to be bypassed.
• 📡 Someone is using WPS (simplified connection by PIN code), which is easy to hack.

Solution:

1. Turn it off WPS in the router settings.
2. Reset your router to factory settings and set it up again.
3. Update your firmware to the latest version.

Can my neighbors connect to my Wi-Fi if the network is hidden (SSID is not broadcast)?

Yes, hiding the network name (SSID) does not protect against connection. An experienced user can:

• 🔍 Find a hidden network using specialized programs (for example, inSSIDer).
• 📡 Connect manually, knowing the network name and password.

Hiding SSID It only makes it more difficult for legitimate devices to connect, but it doesn't improve security. It's better to use complex password And WPA3.

How to check if the router itself is hacked?

Signs of a hacked router:

• 🔄 Unknown redirect rules (Port Forwarding) in the settings.
• 📡 Changed DNS servers (in Settings → Internet).
• 🖥️ Unusual processes in System log router.
• 🔌 Suspicious devices on the list ARP tables.

If you notice any of these:

1. Reset the router to factory settings (button Reset for 10 seconds).
2. Update the firmware from the manufacturer's official website.
3. Change the router administrator password (do not leave it admin/admin!).

Is it possible to track a foreign device using geolocation?

The approximate location of a device on your network can be determined by:

• 📱 Through apps like Fing or NetCut (show the relative signal strength).
• 📡 Using triangulation (if you have multiple access points), but this requires special equipment.

It's impossible to determine a precise geolocation (such as an address) without the involvement of your provider or law enforcement. If there's a serious threat (such as data theft), contact the police with evidence (such as router logs).