Wireless networks also refer as "Wi-Fi". It allows laptops, PCs and other devices to "talk" to each other through radio signals within short-range. However, to create a secure wireless network you will have to make some changes to the way it works after it is switched on.
Signals from any short-distance radio transmission that can be taken by the device in the range are set to the same frequency. This means that any person with a wireless PC or laptop within range of your wireless network can connect so you have to take some precautions.
You can navigate to this website to get more information about securing wireless networks.
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If this happens then your network and PCs are vulnerable to any or all of the following:
Freeloaders – Most wireless networks are used to share a broadband Internet connection. Many Internet services in the home have a limit to the amount of data you can download per month.
Eavesdropping – An "eavesdropper" is transmitted as information to connect to the wireless network and see all the information as it moves. It is completely undetectable by the user as "eavesdropper" just listen do not send it.
Sensitive information such as credit card numbers, bank account details, usernames, and passwords can be recorded.
Hacking – All home wireless network router has a default user name and password for network administration. All hackers have to do is go through the list of default user names and passwords until he gets access. A hacker can then use your network to any of the above or gain access to your PC.
The majority of wireless network equipment, when it comes out of the box, is not protected against this threat by default. This means you have to configure your own network to create a secure wireless network.