1. Introduction

Welcome to the #wireless FAQ page. Look here first for resources and tips on doing your Wifi magic.

Other websites you should look at for help are:

TableOfContents

2. General Linux Stuff

2.1. How do I install <blah> package?

Read [http://www.linux.com/article.pl?sid=03/11/26/1337210 this].

3. Wireless Network Card Questions

3.1. What is the best 802.11b wireless card?

This is a highly subjective question. In my opinion the best all around wireless card is a Lucent/Orinoco Silver or a Gold card. They have good OS support, external antenna jacks, and have one of the highest receive sensitivity on the market. If you are looking to make a HostAp machine, you might want to look into the Zcomax Prism2Card or the [http://www.netgate.com/NL2511.html Senao 200mW cards]. However, many people have reported headaches when using such high powered wireless cards, raising some concerns. I would only recommend this card for point to point links in the boonies. An unofficial support page for [http://www.seattlewireless.net/index.cgi/SenaoCard Senao wireless cards] is maintained by SeattleWireless.

3.2. Will my D-link DWL-650+, 3Com USR2210 (or other TI chipset 22 Mbps hardware) work in Linux or *BSD?

Yes. There's the ACX100 project available at http://acx100.sourceforge.net , which managed to write an OSS driver despite
- not getting any chipset specs from TI, D-Link or USRobotics. Please tell TI, D-link et al. that real Linux support would be greatly appreciated. Note that similarly named cards usually will NOT work with this driver, due to D-Link's highly idiotic product naming policy.

3.3. Will my Broadcom chipset wireless card work in Linux or *BSD? (Linksys wmp11v2.7 and Dell Truemobile 1180 for example)

Maybe. [https://www.linuxant.com/driverloader/ Check here] for a Windows driver wrapper.

3.4. Will my Atmel chipset wireless card work in Linux or OS X? (SMC2632W)

Maybe, look at http://atmelwlandriver.sourceforge.net/news.html
There is an [http://www.russotto.net/~russotto/atmelx.html OS-X driver] available as well.
Linksys has published Atmel source code, available from ftp.linksys.com, specifically [ftp://ftp.linksys.com/pub/network/ATMEL_linux_drivers.tar.gz here]. If not, you're probably out of luck. Contact the manufacturer, and failing that, return the product.

3.5. I'd like to try doing ___________ with 802.11b. Will it work?

Dunno, maybe. Wireless networking depends on so many different factors that it's impossible to say for sure. Try it and let us know.

3.6. Do 802.11a cards work under Linux or *BSD?

There is a Linux driver for Atheros based cards available from http://team.vantronix.net/ar5k/ however this driver is experimental and may not work!
An Atheros gifted driver is available in FreeBSD 5-CURRENT (aka: FreeBSD 5.2). See the [http://www.freebsd.org/cgi/man.cgi?query=ath&apropos=0&sektion=0&manpath=FreeBSD+5.1-current&format=html ath] man page for more details.
Linux drivers are available from the [http://sourceforge.net/projects/madwifi/ Mad Wifi] source forge project. If you have an unsupported chipset, contact the manufacturer, then return the hardware.

3.7. Do 802.11g cards work under Linux?

Apparently, some of them do. There is the [http://prism54.org/ prism54 project] and the [http://sourceforge.net/projects/madwifi/ madwifi project].
[http://returntonature.com/pipermail/linux-sony/2003-September/005565.html Here] is a mini-howto for getting a linksys dual band card to work using the madwifi driver.
If you are using the MadWiFi drivers and the card won't seem to associate with your Access Point, like my (solarce at fallingsnow.net) Netgear WG311 (a good buy, $60 shipped at newegg.com) was.
- Then just follow these easy step for Linux powered 802.11g bliss.
- 1.) (Assuming you've installed the madwifi drivers from cvs and loaded the 'ath_pci' driver) ifconfig ath0 up 2.) iwconfig ath0 ap xx:xx:xx:xx:xx:xx (this is the mac addy of your ap, you can probably find it with 'iwlist ath0 scan') 3.) iwconfig ath0 channel XX (1-11, whatever your wap is set to) 4.) iwconfig ath0 essid your_essid_here 5.) iwconfig ath0 rate XXMB (your rate here, i.e. 11MB, 54MB) 6.) ifconfig ath0 x.x.x.x OR dhcpcd/dhclient/pump ath0 (for dhcp goodness) 7.) Let Cool and Sprinkle with Powdered Sugar (ok not really)
  And now you have 802.11g under Linux, me, I am using the card in my shiny new xp 2700+ powered MythTV machine, (http://www.mythtv.org) Enjoy!

3.8. I'm trying to use my ________ (prism2 chipset card) under linux, and I can't figure out wlan-ng, help!

You might want to try using HostAp ( http://hostap.epitest.fi/ ), it is a driver that supports ad-hoc, infastructure and master modes, and uses the linux wireless extensions, so you can configure it with iwconfig, unlike wlan-ng.

3.9. What driver should I use for Linux?

For lucent/orinoco cards, orinoco_cs, for Prism2/2.5/3 HostAp is strongly suggested, for cisco/aironet cards, airo_cs. You can get rpms of kernels including hostap at http://www.cat.pdx.edu/~baera/redhat_hostap/ These are using the redhat patched kernel source, with hostap included.
<coderman> Chalain : choosing wlan-ng over hostap is like a child accepting a ride fromBR a strange man offering candy with one hand down his pants

3.10. How do I get my Linksys WPC11 to work under Linux?

See http://tldp.org/HOWTO/mini/Wireless-Link-sys-WPC11/
I do not recommend following these directions, as the drivers are not totally compatible with the linux wireless extensions, which are a standard all the other drivers follow. If you choose to use wlan-ng, please don't expect any support what so ever from #wireless. The WPC11 is a prism2 chipset card, try following directions for other prism2 based cards, orinoco_cs and hostap will also work, and both support the linux wireless extensions. --ForrestEnglish

3.11. How can I find out what chipset my network card uses?

Find the FCCID for the card (usually on the card itself) and search the FCC's database: http://www.fcc.gov/oet/fccid/

3.12. I want a wireless network scanner under Linux, or help configuring one, please?

For linux the best option is definitely [http://kismetwireless.net Kismet]. There is a [http://truffula.net/~forrest/kismetorinoco.shtml guide] to setting up kismet 2.8 using linux 2.4.20 and an orinoco wireless card here. Kismet supports prism2 and cisco cards as well (cisco cards, and prism2 using hostap don't require any kernel patches, just follow the directions in the kismet readme files).

3.13. Will my USB wireless adapter work under Linux?

Maybe, support is iffy at best right now. If you are using a prism2 usb adapter, I wish you luck with wlan-ng. If you are using somthing else... I wish you a short trip back to the store.

3.14. How can I find what version of Firmware my Wireless Network card has?

You can find out what firmware you are using by checking /var/log/syslog or /var/log/messages (depending on your distro) when you insert the card. This may or may not work I'm afraid, but you should definitly look.

3.15. I want to install some kind of authentication software for my wireless network, can I do that?

Most access points have mac address limiting options, and also you could enable WEP. Mac addresses can be faked however, and WEP can be broken fairly easily. If you just want to keep causual users off your network, WEP would be your easist solution, just check out the manual of your access point for instructions on enabling this. A better solution might be to use real authentication software like NoCatAuth.
You'll probably want to be comfortable with linux to do this, and use a linux machine as the router either using HostAp or with the access point hooked up directly to the machine. Then you'll want to checkout http://nocat.net for authentication gateway software called NoCatAuth.

4. Antennas and stuff

4.1. dB, dBm, dBi, mW, W.... What is all this stuff?

mW stands for miliwatt, W for watt. Sometimes we talk about watts, but usually we talk about dBm, dB and dBi. Simply put, dBm is the amount of power your radio transmits. dBi is usually the amount of gain your antenna has. You can add dBm and dBi together to find out a rough idea of how much "power" the card and antenna will put out.
For an explanation on the dB stuff, check out the DeciBels page.

4.2. How can I calculate the distance my antenna will have?

It depends what you're transmitting through. First you need to know what your FreeSpaceLoss is. Assuming you have perfect LineOfSight, the FSL at 5 miles is 118.36 dB. At ten miles it's 124.38 dB. Then you do this:
```
 ( txdB + txdbi ) - fsl + ( rxdbi ) 

  where:
    txdB is the amount of power your radio transmits at (in dBm)
    txdBi is the amount of gain your antenna has
    fsl is the amount of loss in dB between the two sides of the link
    rxdbi is the amount of gain the ''recieving'' antenna has.
```
If you do have trees, buildings, bad coax cable or anything else that can impede the radio signal
(besides the open air between the antennas), try and figure out what the loss is in dB and add it to the fsl value. This'll come up with a number, probably negative. This number is the amount of radio energy that receiving side will be able to "hear" (under ideal circumstances that is!). The object of the game is to get the receiving side
hearing a signal of at least 10 dB more than what the receiving radio's FreeNetworks:ReceiveSensitivity is.
You can also use the commands !range, !fsl and !rxsl in the IRC channel to do the math for you.

4.3. What is the best antenna?

There is no right answer to this, please look up the radiation patterns of antennas your are interested in and see if they will fit your needs. Parabolics are good for long distance links, Helicals, Waveguides and Yagis are generally good for medium distance links, Sector antennas are good for medium distance links or large area coverage, and Omni antennas are good for large area coverage.

4.4. How can I hack an antenna onto my wireless card?

If your card doesn't already have an antenna connector, you should return it and buy one that does (ORiNOCO, Cisco, EnGenius/Senao and a few D-Link's have proper connectors). Seriously.

4.5. I want to build my own antenna, where are instructions to do that?

The cantenna is really the only antenna that is even worth building yourself anymore as antenna prices drop slowly, and we realize what a PITA and a time sink it is to build a quality antenna yourself. But, we do understand the desire to build your own when you first get into this wireless stuff, hell, we did. The cantenna is a waveguide antenna made from a tin can, with a copper wire and an N connector, it can be built in 20 minutes and $5 worth of parts, and will give between 8 and 16 dB of gain have been reported.
Here are instructions for the cantenna: http://www.turnpoint.net/wireless/cantennahowto.html

5. Connecting to Networks

5.1. How do I connect to a wireless network?

This is different in each operating system, see AssociationWithNetworks and find your operating system's instructions.

5.2. How do I hack into my neighbors Wireless Network?

Knock on his door and ask if you can use his network. He'll be able to help you get on.

5.3. How do I crack WEP?

see above.

5.4. What system do I need for 902.10 Wireless on my TV

You need what we call a "DMCA Take Down Notice" operating system. Email piracy@mpaa.org with the subject line of "dvd decss movies for free" and give them your full mailing address, as well as a list of what programs and movies you want to get for free over your wireless connection.

6. Network Configuration help

6.1. How do I setup my network to automatically get an IP address?

This is currently covered in NetworkCommands.

6.2. What commands do I need to use?

The NetworkCommands page lists commands used to configure IP address information once you have your radio associated with the access point.

7. How do I make money with WiFi?

Q: I have a great idea on how to serve my local starbucks and makes loads of cash. How do I do it?
A: Go [http://isp-lists.isp-planet.com/isp-wireless/resources/how_to/ here] and don't bug us.

8. Building A HotSpot or Network

8.1. What is a captive portal?

See CaptivePortal

8.2. What captive portal/gateway software is available?

See PortalSoftware

9. Security Concerns

9.1. How broken is WEP, anyway?

WEP isn't secure, period, if you're interesting enough for someone to devote a lot of time to hack you. if you just want to keep people off your network, it should be fine.

9.2. So what should I use, then?

You should examine the various device level standards supported by your vendor, such as WPA/802.11i and 802.1x. Also, you might want to consider IPSEC, PPTP, or another VPN solution. These would allow you to secure your own traffic from eavesdroppers, while still allowing open access (without using a seperate AP for a secure channel).

10. Who is WifiFred?

WifiFred is our IRC Bot, he maintains a database of various Wireless and Internet related things like Cable types and Internet Standards. He also does simple calculations on Fresnel zones and Path Loss. For brief help, use !help .
See WifiFred for a complete command reference and additional information.

11. Someone posted a URL a while back but I forgot what it was!

If you remember part of the URL, or the URL's description, you can try [http://www.bcwireless.net/wififred/url.php searching] the WifiFred's URL database.

Help with windows specific stuff in NetworkCommands and AssociationWithNetworks would be greatly appreciated. I have pictures and commands for the orinoco software under windows that I can take care of, but anything else is fair game. Further wikiizing this page (like the lucent cards), and any further FAQ's would also be welcome --ForrestEnglish

[CategoryDocumentation]