WEP key

The first and simplest thing you can do is check your wireless network connection and see if it is safe. When you install your router, you are given the option key setting wireless encryption protocol (WEP). Basically this is a password-protected method to log on to your own wireless network. If you do not have it, you operate an open network. That means anyone within range can use your wireless for free. While this is not hacking, but it is debatable whether this is actually a steal. In any case, if you do not have a WEP key, then you are vulnerable to illegal access of WiFi network connection.

 Even if you have a WEP key, it does not mean that your neighbors can not pass it. To determine whether someone is logged into your wireless network, you can do so by checking the logs your wireless network. To do so, click the Start Menu in Microsoft Windows, then double-click My Network Places. Next, double-click View Entire Network. If there are more devices connected than you have or allowed on your network, then it seems there is a WiFi thief.

 A similar method for determining the status of WiFi user list is to check your router's DHCP client table. Just as I view the network, the DHCP client table would list the machines on your network connection. If the number exceeds what you set up, it is possible someone is stealing your WiFi.