ZyXEL Communications P-873HNU-51B, Руководство пользователя

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Chapter 7 Wireless
P-873HNU(P)-51B User’s Guide
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Because of the damage that can be done by a malicious attacker, it’s not just people who have
sensitive information on their network who should use security. Everybody who uses any wireless
network should ensure that effective security is in place.
A good way to come up with effective security keys, passwords and so on is to use obscure
information that you personally will easily remember, and to enter it in a way that appears random
and does not include real words. For example, if your mother owns a 1970 Dodge Challenger and
her favorite movie is Vanishing Point (which you know was made in 1971) you could use
“70dodchal71vanpoi” as your security key.
The following sections introduce different types of wireless security you can set up in the wireless
network.
7.7.3.1 SSID
Normally, the VDSL Router acts like a beacon and regularly broadcasts the SSID in the area. You
can hide the SSID instead, in which case the VDSL Router 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 wireless
devices to get the SSID. In addition, unauthorized wireless devices can still see the information that
is sent in the wireless network.
7.7.3.2 MAC Address Filter
Every device that can use a wireless network has a unique identification number, called a MAC
address.
1
A MAC address is usually written using twelve hexadecimal characters
2
; for example,
00A0C5000002 or 00:A0:C5:00:00:02. To get the MAC address for each device in the wireless
network, see the device’s User’s Guide or other documentation.
You can use the MAC address filter to tell the VDSL Router which devices are allowed or not allowed
to use the wireless network. If a device is allowed to use the wireless network, it still has to have
the correct information (SSID, channel, and security). If a device is not allowed to use the wireless
network, it does not matter if it has the correct information.
This type of security does not protect the information that is sent in the wireless network.
Furthermore, there are ways for unauthorized wireless devices to get the MAC address of an
authorized device. Then, they can use that MAC address to use the wireless network.
7.7.3.3 User Authentication
Authentication is the process of verifying whether a wireless device is allowed to use the wireless
network. You can make every user log in to the wireless network before using it. However, every
device in the wireless network has to support IEEE 802.1x to do this.
For wireless networks, you can store the user names and passwords for each user in a RADIUS
server. This is a server used in businesses more than in homes. If you do not have a RADIUS server,
you cannot set up user names and passwords for your users.
Unauthorized wireless devices can still see the information that is sent in the wireless network,
even if they cannot use the wireless network. Furthermore, there are ways for unauthorized
1. Some wireless devices, such as scanners, can detect wireless networks but cannot use wireless networks. These kinds
of wireless devices might not have MAC addresses.
2. Hexadecimal characters are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, and F.