ZyXEL Communications VMG1312-T10C, User Manual

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Chapter 6 Wireless
VMG1312-T10C User’s Guide
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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 very 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 - for example, a three-letter word from the dictionary.
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.
6.10.2.1 SSID
Normally, the Device acts like a beacon and regularly broadcasts the SSID in the area. You can hide
the SSID instead, in which case the Device 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.
6.10.2.2 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
wireless users to get a valid user name and password. Then, they can use that user name and
password to use the wireless network.