Chapter 5 Wireless LAN
In this wireless network, devices A and B are called wireless clients. The wireless clients use the access point (AP) which is connected to a WLAN controller to interact with other devices (such as the printer) or with the Internet. Your
Every wireless network must follow these basic guidelines.
•Every wireless client in the same wireless network must use the same SSID. The SSID is the name of the wireless network. It stands for Service Set IDentity.
•If two wireless networks overlap, they should use different channels.
Like radio stations or television channels, each wireless network uses a specific channel, or frequency, to send and receive information.
•Every wireless client in the same wireless network must use security compatible with the AP.
Security stops unauthorized devices from using the wireless network. It can also protect the information that is sent in the wireless network.
5.2Wireless Security Overview
The following sections introduce different types of wireless security you can set up in the wireless network.
5.2.1 SSID
Normally, the AP acts like a beacon and regularly broadcasts the SSID in the area. You can hide the SSID instead, in which case the AP does not broadcast the SSID. In addition, you should change the default SSID to something that is difficult to guess.
This type of security is fairly weak, however, because there are ways for unauthorized devices to get the SSID. In addition, unauthorized devices can still see the information that is sent in the wireless network.
5.2.2 User Authentication
You can make every user log in to the wireless network before they can use it. This is called user authentication. However, every wireless client in the wireless network has to support IEEE 802.1x to do this.
For wireless networks, there are two typical places to store the user names and passwords for each user.
•In the AP or WLAN controller: this feature is called a local user database or a local database.
•In a RADIUS server: this is a server used in businesses more than in homes.
If your AP or WLAN controller does not provide a local user database and if you do not have a RADIUS server, you cannot set up user names and passwords for your users.
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