How to find out if a stranger has connected to your wireless network

The security of wireless networks is very important these days. You don't need someone to use the bandwidth of your internet connection or connect to your network to carry out hacker attacks. Each wireless router is different, so this article will cover the basic steps, using the Linksys WAP54G router as an example. The exact steps for your router may differ from those described. This article assumes that you are using DHCP correctly when connecting to your router (via cable or wireless).

Steps

Tell If an Outside User Is on Your Wireless Network Step 1

Step 1. Launch a web browser and then enter the IP address of the default gateway

To find it:

Open the start menu, click Run and type cmd
Type ipconfig and press Enter. The default gateway address will be displayed. Now open your web browser and enter the gateway address in the address bar of your browser.

Tell If an Outside User Is on Your Wireless Network Step 2

Step 2. Enter the username and password for the router

For Linksys routers, the default credentials are: Username - None; the password is admin.
For Netgear routers, the default credentials are: username - admin; password - password.
For Dlink routers, the default credentials are: username - Admin; password is missing.
For Siemens routers, the default credentials are: username - Admin; the password is admin (only lowercase letters).
For zyxel-p600-t1a router, the default password is 1234.
The default usernames and passwords can be found on the router case or on the Internet.
If you cannot find your credentials, go to http://www.portforward.com. This website is commonly used to open ports for peer-to-peer games and programs, but when it explains how to open ports, it shows the router credentials. The list of routers is extensive.

Tell If an Outside User Is on Your Wireless Network Step 3

Step 3. If you are using the default username and password, click on the “Administration” tab to change them to secure

On the router's configuration page, find and enable the option to register users connecting to the router.

Tell If an Outside User Is on Your Wireless Network Step 4

Step 4. Take some paper and a pen, find out (as described above) the default gateway address to find and write down the MAC addresses of computers / devices that are or will be connected to your wireless network

Check your MAC address list regularly to see if it contains unknown addresses; if so, an unauthorized user has connected to your network. The MAC address is a unique hexadecimal code that identifies the network cards of computers connected via Ethernet cables. No two MAC addresses are the same.

Method 1 of 2: How to find a rogue device on your network

Tell If an Outside User Is on Your Wireless Network Step 5

Step 1. Click on the “Setup” tab

Tell If an Outside User Is on Your Wireless Network Step 6

Step 2. Scroll down to DHCP-server

Activate this option (if it is disabled).

Tell If an Outside User Is on Your Wireless Network Step 7

Step 3. Click on “Status”> “Local network” under the main tabs

Tell If an Outside User Is on Your Wireless Network Step 8

Step 4. Click on DHCP Clients Table

A list of computers that are connected to your network via DHCP will be displayed (DHCP automatically configures the IP and DNS addresses of the computer). This will only work if all connected devices are using DHCP. Devices with static addresses will not be listed.

Method 2 of 2: Other Methods

Tell If an Outside User Is on Your Wireless Network Step 9

Step 1. Install and run the "Who Is On My Wireless" program

Tell If an Outside User Is on Your Wireless Network Step 10

Step 2. Click “Scan now” to display a list of devices connected to your network

Tell If an Outside User Is on Your Wireless Network Step 11

Step 3. Open the configuration page of the router and go to the list of connected devices

If you spot an unknown device, block its MAC address.

Advice

To get your own IP address, disable the DHCP server on your router. But in this case, other users will not be able to connect to your network (until they find out the address).
Install a firewall on your computer to prevent hacker attacks.
Turn off your wireless router when not in use.
Once connected to the network, disable the broadcast function to prevent the router from broadcasting its name. You will still be able to connect since you know the name.
If you are worried about people connected to your network, go to the Wireless tab, click Security and enable WPA or WPA2. Anyone who wants to connect to the network will need a WPA or WPA2 key. Don't use WEP because it takes a minute to crack.
Turn on MAC address filtering. Allow only devices with known MAC addresses to connect to the network. This is a fast security option, but MAC addresses are transmitted in clear text between devices and the router. A potential attacker could use a packet sniffer to find out your MAC address and then perform MAC spoofing to trick the router.
Remember that the methods described here (with the exception of activating WPA / WPA2) will not prevent people from connecting to your network. It just complicates the connection process a little for an inexperienced user.
Use a different subnet. In this case, no one will know if your DHCP server is turned off. To do this, simply change the default IP address of the router (on the configuration page). For example, replace 192.168.1.1 with 192.168.0.1.
Change your network password every one to two months and always use WPA2-PSK with AES encryption.

Warnings

Make sure not to disrupt the network.
Make sure you have access to the chassis of the router in case you need to do a factory reset.
Always check if WPA2-PSK and AES encryption are enabled.