Difference between revisions of "Wireless Networking"


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<b>Configuring the WG111 to use WPA-PSK on a wireless network</b>
 
<b>Configuring the WG111 to use WPA-PSK on a wireless network</b>
  
This card works very well in Knoppix 3.9, but is as of yet untested in other versions (to my knowledge).
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This card works very well in Knoppix 3.9 using ndiswrapper, but is as of yet untested in other versions of Knoppix (to my knowledge).
  
 
*'''Commands:
 
*'''Commands:

Revision as of 23:34, 6 September 2005

Wireless Networking Overview

Wireless networking (or wifi) allows you to network computers and related equipment (print servers, cameras, and other devices that connect by ethernet) without the need to run wires between equipment.

The advantages: Greater flexability in equipment location, no need to run network cable throughout your building, ease of moving equipment, easy and clean to add new users (such as at a wifi enabled "Hot Spot" coffe shop or airport terminal). The disadvantages: extra cost, slower speed than wired connections, connections are usually not as reliable, interference from other equipment including cordless phones and microwave ovens, security issues, extra compexity in setting the wireless network up, extra power usage in a notebook (usually significantly reducing battery life per charge), and manufacturers usually not releasing open source drivers for Linux or even specs for the wireless chips that would allow developers to write free high quality drivers.

There are many versions of wifi equipment available. Common versions are 802.11b, a standard that runs at 11mbit/second and 802.11g, which runs at 54mb/s. 802.11g equipment can also work with 802.11b, although when you mix them the entire network often slows to the 802.11b speed. Both 802.11b and 802.11g equipment works on the unlicensed 2.4 ghz band, a band that is frequently used by cordless phones, and is close in frequency to the frequency of microwave ovens. There is another standard, 802.11a, that uses a different (higher) frequenct band. 802.11a equipment is not usually fond in the home consumer market. There are also many newer proposed standards, with many manufacturers offering faster next generation equipment even before these standards are finalized. There are also other wirelsss technologies used for other things, such as Bluetooth and wireless mice and keyboards, which are beyond the scope of this wiki article.

The range of wifi connections varys greatly with the equipment used and the location, but is typically 50 to 100 feet. It is greater outdoors than in a building with many walls or transmitting through floors. Even minor changes in transmitter and/or receiver location can significantly affect reception. Frequently users in apartment complexes will find that they can receive signals from other wifi users, or that their own signals can be received by others. It may be ncessary to make setting in the wifi equipment to move a user to a different channel to avoid some interference.

Wifi equipment uses the same band but not the exact same channels in different countries. If you travel with wireless equipment you may still be able to connect to wifi equipment when outside your country, but you should check that your equipment is not operating on channels that are illegal to use in that country.

802.11b tends to be less expensive than 802.11g. It is slower, but at 11 mb/s it is still fater than the internet connection of most users, so if you plan on using wireless networking mainly for Internet access this may be a non-issue. Older 802.11b equipment is also usually much better supported in Linux than 802.11g, when it is supported at all.

To set up a wireless network you need a wireless network interface adapter (NIC) for each computer that will not have a wired ethernet connection. You should expect to also need a wireless router that the wireless computers will all connect to and that will connect to your Internet modem. There are devices called "access points" that can be attached to an existing network that includes one or more routers, but an access point without a router is not enough. The internet modem must support an ethernet connection to attach to a router. You can not attach a Internet modem with a cheap USB only connection to a router. Home routers, even wireless routers, have dropped greatly in price recently and are now very affordable.

Linux Wireless Network Issues

Unfortunately, most Wireless card makers and even the chip makers who make many of the integrated circuits used in the wireless adapters are not releasing programming information for how their cards and chips work. Many manufacturers are also only releasing software drivers for their products for the Windows operating systems. That has caused problems and delays in Linux's support of wifi devices. If the software developers who do networking support for Linux had good programming spefications for these devices we would not only have good drivers for them, but would likely also have software that can use them for other interesting and unique applications, since there seems to be a lot of software control of these programable radio devices.

Some software drivers have been released for some devices. Occasionally a manufacturer may even claim the driver is "open source", but the source code is not available and the driver that is available is released only as a pre-compiled module. Often these drivers are unreasonably large and their size would prevent many of them from being incorporated into the Knoppix CD.

With the above said, Knoppix is improving in it's ability to detect and support wireless devices. If the device you own does not work with the ciurrent Knoppix release, be sure to check it as future releases come out.

For cards where there has only been a Windows driver released, another approach that has been tried is to use special translation software that will allow software drivers written for Windows to run in the Linux operating system. This translation software is named ndiswrapper. With ndiswrapper you can attempt to load a driver written for Windows and run your card under Linux. Recent versions of Knoppix do include ndiswrapper, but they do not include the Windows drivers, so you will need the Windows driver for your device to try to use this approach. Some users have had good results with ndiswrapper, other times the Windows driver will not work with it.

Linux support for wifi equipment at this time seems to be much better for PCMCIA (PC) cards and for PCI cards than for USB devices. USB adds an extra level of complexity, and USB isn't really well suited for networking, even though this equipment is widely available. Users would be well advised to select types of network interfaces other than USB. Also, the support there is tends to be better for older 802.11b equipment than 802.11g and newer equipment, but 802.11g support is reported to be improving.

Wireless Networking Security Issues

This is a stub for this section, to be added shortly

General Information On Wireless Card Setup Under Knoppix

This is a stub for this section, to be added shortly


The below sections are specific information on specific make and models of Wireless Networking Adapters and information we currently have on if they are supported in Knoppix or not. Please add your results with your card to the list, and please try to keep the list in alphabetical order. Please do not post questions about wireless adapters here, those should be submitted in the Networking Forum.

Belkin

Belkin 802.11b 11Mbps PCMCIA card

This 802.11b pcmcia card (pc card) was detected by Knoppix 3.7 (maybe by prior versions too), but I could not get it to operate properly. Starting with Knoppix 3.8.1 it was detected and worked perfectly. ndiswrapper is not needed. My card is marked ver. 2101 on the box, no other model number is given. If your card is not ver. 2101 it may or may not use a different chip set.

D-Link

Here is a link to a D-link page that claims to tell you which D-link cards have "open source" drivers and which do not.

http://support.dlink.com/faq/view.asp?prod_id=357&question=General%20Wireless

However, it is worth mentioning that in most or all of these cases the drivers are not really "open source", they are precompiled modules that the source code is not available for. And in some cases they are insanely bloated, the "driver" for my card is about 2 megs in size just for a driver! Note that not all of these cards are supported by Knoppix and it is extremely unlikely that even if the license permits it that a sepcific card driver will ever be included in Knoppix if it is several megs in size.

D-Link DWL-650

This is a very common and inexpensive 801.11b pcmcai card offered by D-link. Unfortunately, D-Link has actually released a number of different versions of this card that use completely different chipsets from different intigrated circuit manufacturers all under the same model number. The D-Link website can be used to identify which version you have, but the version number may not be marked on the outside of the box when you buy this card, so it may be a problem to find one that works under Knoppix.

There are reports that some versions of this card are detected and work under Knoppix. See this thread in the forums: http://www.knoppix.net/forum/viewtopic.php?t=19759&highlight=dwl650 However, I have two DWL-650 cards and so far they have not been detected by Knoppix.

D-Link DWL-G650

This stub to be replaced with info on this card "real soon now". Util then there is information in this forum article: http://www.knoppix.net/forum/viewtopic.php?t=20915

Orinoco Gold

This was one of the first and best supported wireless 802.11b pcmcia cards under Linux. It is still one of the best cards for compatability, not just with Linux, but with several networking programs that work under Linux like NETstumbler and airsnort. Unfortunately, it tends to be very overpriced and can usually not be found at major retailers, but must be obtained mail order, if available at all.

Linksys

Linksys WPC55AG

Here is a link to a forum discussion about this card: http://www.knoppix.net/forum/viewtopic.php?t=12351

Netgear

Netgear WG111

Configuring the WG111 to use WPA-PSK on a wireless network

This card works very well in Knoppix 3.9 using ndiswrapper, but is as of yet untested in other versions of Knoppix (to my knowledge).

  • Commands:

Assuming that the drivers are on the cd in /dev/cdrom, then

mount /dev/cdrom/ /mnt/cdrom/

Find ndiswrapper configuration under Knoppix->Network/Internet and select netwg111.inf from /mnt/cdrom. After that finishes, create the configuration file that you will need shortly using the following command:

wpa_passphrase MySSIDHere MyPassphraseHere > /home/knoppix/wpa_supplicant.conf 

Now, use your favorite text editor (if you don't have one, try Kate under the menu item Editors) and edit the /home/knoppix/wpa_supplicant.conf you just created (see sample below).

With that completed, run the following command. Warning: As it is, the command will monopolize your current command window with potentially useful debugging output, including your encryption key; add -B if you would rather run it in the background (useful when you know it works already), remove -K to hide your key.

sudo wpa_supplicant -ddKt -i wlan0 -c /home/knoppix/wpa_supplicant.conf -Dndiswrapper

The following grabs an IP address if you use DHCP from your router.

sudo pump -i wlan0

And finally, tell Knoppix where to go to find the internet.

sudo route add default gw <Gateway/Router IP address here> 
  • wpa_supplicant.conf

Note: the bold lines were added in the editing steps for my Linksys WRT54G Router to accept the card. See the Useful Links at the end for a full explanation of all options that can be put in here.

ctrl_interface=/home/knoppix/wpa_supplicant
eapol_version=1
ap_scan=1
network={
ssid="MySSIDHere"
scan_ssid=1
#psk="MyPassphraseHere"
psk=hex representation of the passphrase
proto=WPA
key_mgmt=WPA-PSK
pairwise=TKIP
group=TKIP
}
  • Useful Links:

Wireless card success story (where I located the pump command)

Example wpa_supplicant.conf with full explanations and various configurations

-bobeltomate

Netgear WG311 v2 PCI

See this article in the forum: http://www.knoppix.net/forum/viewtopic.php?p=90075#90075