Wireless Internet access is available in many coffeehouses, parks,
schools, offices and homes. You will normally be accessing through
a wireless access point, which is a device that routes traffic in
a wireless network. Wireless access points are normally attached
to an excisting wired network, or through a Wide Area Network (WAN)
connection such as cable and xDSL.
Supported hardware
Zeta has support for the following wireless cards and adapters:
- PCI adapters
- PCMCIA cards
- USB adapters
Some cards are supported out of the box and others need to be
configured, for Zeta to make use of them.
If your card doesn't work, please read this tutorial.
Wireless Networking Modes
There are two modes in which you computer can connect to a wireless
network:
- Ad-hoc mode: A wireless network where two or
more computers communicate with one another directly (Basic Service
Set - BBS or Independent Basic Service Set - IBSS).
- Infrastructure mode: A wireless access point is used
to route the network traffic from one computer to another.
What is the difference between 802.11a/b and g ?, and what standards
are supported in Zeta ?
802.11a
The a standard provides data rates up to 54 Mbps, and is working
in the 5GHz band. The 802.11a standard seem to suffer compared to
the b standard, as the signals at 5GHz appear to travel only half
as far as signals at 2.4GHz. The advantage is that the 5 GHz band
is less used than the 2.4 one (micro ovens, Bluetooth, ...) and
has a better density of stations than 802.11b.
The standard is currently not supported in Zeta.
802.11b
802.11b is the de facto wireless networking standard of the last
few years. The standard provides data rates up to 11 Mbps, and is
working in the 2.4GHz band. 802.11b will automatically select the
best data rate (1, 2, 5.5, or 11Mbps), depending on available signal
strengths.
Millions of 802.11b devices have been shipped, and the cost of
client and access point gear (basestations) is not only low, but
many laptops and handheld devices now ship the 802.11b connectivity.
The standard is supported in Zeta for some chipsets, for example
the Intersil Prism 2/2.5/3 chipsets family. There is a lot of other
chipsets unsupported. Make sure to check the yellowTAB Supported
Hardware Compatibility Database.
802.11g
802.11g has brought 54Mbs connectivity to the 2.4GHz band, all while
keeping backwards compatibility with excisting 802.11b gear.
The standard is currently not supported in Zeta.
WEP and WPA
WEP
Wired Equivalent Privacy (WEP) is an encryption for the 802.11b
standard. The encryption is done at the MAC layer, and only clients
who know the "key" can associate with the wireless network.
If you don't have the needed "key", you will still be
able to see the network traffic, but every packet is encryted.
The encryptions are 40 or 128 bit, and are developed by RSA
Data Security. Most cards that use 802.11b supports these encryption
standards.
The WEP encryption is far from perfect, as all your communications
are only protected up to the gateway and not further. Once it hits
the wire, your packets are sent in the clear. A just as big problem,
is that other legitimate wireless clients who have the "key"
can read your packets, as the "key" is shared across all
clients.
WEP was not designed to be the "killer" security tool,
only to provide such as great protection that you would have when
you physically plug into your Ethernet network.
Zeta supports WEP encryption 64 or 128 bits encryption for the
Intersil Prism chipset family.
WPA 1.0 and 2.0
The IEEE 802.11g standard has received encryption standard Wi-Fi
Protected Access (WPA).
WPA is set to replace its inferior predecessor, WEP in that WPA
addresses the security concerns associated with WEP. With WEP, users
experienced lack of security due to weak encryption and static encryption
keys. WPA is designed to fix these problems and replace WEP with
a new, stronger encryption algorithm.
Zeta does not support these two new standards.
MAC address filtering
In order to uniquely identify each computer on a network, every
network adapter is assigned a hardware address known as the Media
Access Control (MAC) address.
With MAC filtering enabled on the access point, it will keep an
internal table of MAC addresses that are permitted to use the access
point. Only computers using one of the MAC addresses listed here,
will be allowed to associate with the access point. The MAC address
of a wireless network card should be printed on the back of it (and
looks more or less like this: 12:ab:34:cd:ef:56).
SSID
The Service Set Identifier (SSID) acts as a name for the wireless
network. All the devices connecting to that network must specify
it's SSID. If you are concerned about unauthorized users connecting
to your access point, you should disable SSID broadcast in the access
point's configuration.
Channels
The 802.11b standard has defined 14 channels that are particular
fequencies selected so that a wifi adapter and an access point can
communicate at an agreed frequency. In the U.S., only channels 1
to 11 are used. In Europe, an additional two channels are allowed.
Japan allows all fourteen channels used.
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