ZyXEL Communications CellPipe 7130 RG, Руководство пользователя

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Chapter 7 Wireless LAN
CellPipe 7130 RG User’s Guide
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network’s name. This helps you identify your wireless network when wireless
networks’ coverage areas overlap and you have a variety of networks to choose
from.
Radio Channels
In the radio spectrum, there are certain frequency bands allocated for unlicensed,
civilian use. For the purposes of wireless networking, these bands are divided into
numerous channels. This allows a variety of networks to exist in the same place
without interfering with one another. When you create a network, you must select
a channel to use.
Since the available unlicensed spectrum varies from one country to another, the
number of available channels also varies.
Wireless Security
By their nature, radio communications are simple to intercept. For wireless data
networks, this means that anyone within range of a wireless network without
security can not only read the data passing over the airwaves, but also join the
network. Once an unauthorized person has access to the network she/he can
either steal information or introduce malware (malicious software) intended to
compromise the network. For these reasons, a variety of security systems have
been developed to ensure that only authorized people can use a wireless data
network, or understand the data carried on it.
These security standards do two things. First, they authenticate. This means that
only people presenting the right credentials (often a username and password, or a
“key” phrase) can access the network. Second, they encrypt. This means that the
information sent over the air is encoded. Only people with the code key can
understand the information, and only people who have been authenticated are
given the code key.
These security standards vary in effectiveness. Some can be broken, such as the
old Wired Equivalent Protocol (WEP). Using WEP is better than using no security at
all, but it will not keep a determined attacker out. Other security standards are
secure in themselves but can be broken if a user does not use them properly. For
example, the WPA-PSK security standard is perfectly secure if you use a long key
which is difficult for an attacker’s software to guess - for example, a twenty-letter
long string of apparently random numbers and letters - but it is not very secure if
you use a short key which is very easy to guess.
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.