Appendix B: Wireless Security; Security Precautions; Security Threats Facing Wireless Networks - Linksys Instant Wireless Series User Manual

to maintain a single logical channel. To an unintended receiver, FHSS appears to be
short-duration impulse noise. Direct-Sequence Spread- Spectrum (DSSS) generates a redundant
bit pattern for each bit to be transmitted. This bit pattern is called a chip (or chipping code). The
longer the chip, the greater the probability that the original data can be recovered. Even if one or
more bits in the chip are damaged during transmission, statistical techniques embedded in the
radio can recover the original data without the need for retransmission. To an unintended receiver,
DSSS appears as low power wideband noise and is rejected (ignored) by most narrowband
receivers.
Would the information be intercepted while transmitting on air?
WLAN features two-fold protection in security. On the hardware side, as with Direct Sequence
Spread Spectrum technology, it has the inherent security feature of scrambling. On the software
side, WLAN offers the encryption function (WEP) to enhance security and access control.
What is WEP?
WEP is Wired Equivalent Privacy, a data privacy mechanism based on a shared key algorithm, as
described in the
IEEE 802.11 standard.

Appendix B: Wireless Security

Linksys wants to make wireless networking as safe and easy for you as possible. The current
generation of Linksys products provide several network security features, but they require specific
action on your part for implementation. So, keep the following in mind whenever you are setting up
or using your wireless network.

Security Precautions

The following is a complete list of security precautions to take (at least steps 1 through 5 should be
followed):
1. Change the default SSID.
2. Disable SSID Broadcast.
3. Change the default password for the Administrator account.
4. Enable MAC Address Filtering.
5. Change the SSID periodically.
6. Use the highest encryption algorithm possible. Use WPA if it is available. Please note that this
may reduce your network performance.
7. Change the WEP encryption keys periodically.

Security Threats Facing Wireless Networks

Wireless networks are easy to find. Hackers know that in order to join a wireless network, wireless
networking products first listen for "beacon messages". These messages can be easily decrypted
and contain much of the network's information, such as the network's SSID (Service Set Identifier).
Here are the steps you can take:
Change the administrator's password regularly. With every wireless networking device you
use, keep in mind that network settings (SSID, WEP keys, etc.) are stored in its firmware. Your
network administrator is the only person who can change network settings. If a hacker gets a hold
of the administrator's password, he, too, can change those settings. So, make it harder for a
hacker to get that information. Change the administrator's password regularly.
SSID. There are several things to keep in mind about the SSID:
1. Disable Broadcast
2. Make it unique
3. Change it often
Most wireless networking devices will give you the option of broadcasting the SSID. While this
option may be more convenient, it allows anyone to log into your wireless network. This includes
hackers. So, don't broadcast the SSID.
Wireless networking products come with a default SSID set by the factory. (The Linksys default
SSID is "linksys".)
Hackers know these defaults and can check these against your network. Change your SSID to
something unique and not something related to your company or the networking products you use.