Network - Wireless Networking

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Alert!
Various aspects of wireless networking have made their way in to international news, including strange tales of WarChalking, WarDriving, and Pringles - www.securityfocus.com

Info
Wardriving involves people using their notebooks (equipped with wireless cards and GPS receivers) and driving around the area looking for the presence of wireless networks - just for the fun or to access the security risks of wireless networks. With the GPS receiver, wardrivers can catalog the exact location of an access point.

IEEE
Institute of Electrical and Electronics Engineers - the international body that ratifies new standards for the electronics and computer industries.

Mbps
Megabits per second, used to describe the speed of data transfer across a network or Internet connection.

Router
This is a device that allows you to connect multiple computers to a network or Internet connection.

Network - Wireless Networking

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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