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How to Make Your 802.11b/g Wireless Network More Secure
Microsoft Knowledge Base Article - 309369,
This article was previously published under Q309369
SUMMARY
Wireless networks can be vulnerable to a malicious
outsider gaining access because of the default settings
on some wireless hardware, the accessibility that
wireless networks offer, and present encryption methods.
The concepts that are presented in his article are
general suggestions, and may help make your wireless
network more difficult for a malicious outsider to gain
access. For more specific information about the
implementation of these suggestions, see the
documentation for your wireless network hardware or
contact the hardware vendor.
The 802.11b/g standard permits Wired Equivalent Privacy (WEP)
encryption. Depending on the manufacturer and the model
of the network adapter and access point, there are two
levels of WEP typically available: 64-bit encryption
based on a 40-bit encryption key, and a 24-bit
initialization vector, and 128-bit encryption based on a
104-bit key and a 24-bit initialization vector. In
addition to enabling WEP, there are other steps that you
can take to make your home or small business local area network (LAN) more
secure.
MORE INFORMATION
Making your Wireless Network More Secure
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Enable the highest level of WEP that your hardware
provides. WEP provides some security and is
effective in deterring casual attempts by outsiders
to infiltrate your network. Most 802.11b/g certified
products can use basic 64-bit WEP encryption. By
default, however, 64-bit WEP encryption may be
disabled.
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Change the default Service Set Identifier (SSID)
and passwords for your network devices. Access
points/wireless routers ship from the manufacturer
with default SSID and passwords which is the same on
all devices made by that manufacturer. Leaving these
at default makes it easy for a malicious outsider to
gain access.
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Do not change the SSID or password to reflect your
name, address, or anything that would be easy to
guess. Use upper and lower case letters, numerals
and symbols for the password, if the hardware
supports this.
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If your access point allows, turn
off broadcast SSID. This will put the unit in a
stealth type mode. -
As you survey your home or small
business for access point
deployment, think about locating the access point
toward the center of your location instead of near the
windows. Plan your coverage to radiate out to the
windows, but not beyond. If the access points are
located near the windows, a stronger signal will be
radiated outside your location making it easier for
those outside the building to locate your network.
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Take a notebook computer that is equipped with a
wireless network adapter, and go outside your
location
and survey what range you get in moving around your
property or neighborhood. You may be surprised how
far the signal radiates. If you can connect from
three or four buildings away, so can someone else.
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Some access points allow you to control access
based on the media access control address (MAC
Address) of the
network adapter trying to associate with it. If the
media access control address of your adapter is not
in the table of the access point, you will not
associate with it. If your access point has this
feature, enable it and add the media access control
addresses of each computer's network adapters you use.
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If your access point is also a wireless router,
think about assigning static IP addresses for your
wireless adapters and turn off DHCP. By not
automatically assigning IP addresses to clients who
access the network, it makes it a little more
difficult for an outsider to gain access. Also
consider changing the IP subnet to a different
subnet that does not route on the Internet. Many
wireless routers default to the 192.168.1.0 network
and use 192.168.1.1 as the default router. If you
have 5 computers or devices you could change this to
a limited range such as 192.168.168.1 through
192.168.168.5 -
Purchase access points and network adapters that
support 128-bit WEP. Some products only support
64-bit (40 bit key) WEP, and are not as secure. Note
that some adapters may only require a driver upgrade
to attain 128-bit WEP capability. To obtain
additional layers of security, check for support for
WPA, 802.11i, 802.1x, VPNs, LEAP, PEAP, TKIP, MIC,
FAST, WEP or others. -
Purchase an access point that has a flashable
firmware. There are a number of security
enhancements that are being developed, and you want
to make sure that you can upgrade your access point
as these become available.
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Some products support additional security features
that are either not defined by the 802.11b/g standard,
or not mandated by the standard. Products that use a
propriety security method will only work with
products from the same manufacturer, but can enhance
the security of your network.
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Use a combination of the previous suggestions.
Some editing by Russ Seeney,
www.PBSHawaii.com
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