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The essential settings needed to establish a wireless connection are the same for any O/S. ESSID, mode, transmission rate, channel, encryption type and key are all used by a Linux client just as they are in Windows.
For the wireless device to function, you need to have the proper driver installed and loaded.
Finally, getting the wireless to connect is a great first step. Basic network parameters still need to be configured. Whether you use DHCP or manually configure it, the interface needs an IP address, DNS info and a gateway to talk to the outside world.
A lot. Linux doesn't hold your hand on a wizard-guided journey for other things. Why would it do so with wireless? You'll interact differently to set it up and, probably, use it.
What do I need?
For a laptop, the Card Services and Wireless Tools packages.
Card Services package:
This package is the engine for the PCMCIA portion of a system - usually a laptop. Most Linux distributions will load this when they detect it, but not always. Make sure that Card Services is loaded for your installation.
This software provides essential commands for controlling your wireless device.
Is my card compatible?
Probably. There are open source or proprietary drivers for most wireless devices. The trick is usually knowing what you have.
Not all wireless devices are the same. Even cards of the same make and model may contain different innards. The chipset used in the device determines the driver you'll need.
What chipset do I have?
Use the command ls (or ls -v for more details) to list the devices on a particular bus.
For Mini-PCI or Cardbus devices: lspci
For USB: lsusb
For PC Cards (PCMCIA): cardctl ident
Probably the most complete list of wireless clients and the chipsets in them is at Absolute Value Systems: »www.linux-wlan.org/docs/wlan_ada···.html.gz . Note that this site recommends the wlan_ng drive for many of the cards for which other options exist. See the drivers section for more on this.
What driver do I need?
Often called the kernel drivers since they are included with the Card Services package, David Hinds' orinoco drivers are something of a standard. Don't let the name fool you, these drivers work with a variety of chipsets and with PCI as well as PCMCIA.
The wlan_ng are designed to take advantage of Prism chipset features. They are more complicated to install than some drivers and "break" wireless tools, but work reliably for many folks. If you're using Prism USB, they may be your only option.
These are obsoleted by the orinoco drivers and only work with one group of (now ancient) cards. Don't bother.
For Atmel chipsets, you have two choices:
For Atheros-based cards, you'll need the MadWiFi driver. Building and loading this driver can be a bit tricky. Check the Wiki and the FAQ as well as the driver documentation.
Some companies have refused to develop their own Linux drivers or release enough information to the community to allow open source development, Broadcom and Intel chief among them. For these cases, putting a Linux "wrapper" around the Windows drivers provides Linux functionality. Linuxant has a commercial offering. Ndiswrapper is an open source alternative.
Some wireless applications require patched drivers to operate fully in certain modes; Kismet and Airsnort, for example.
The Host AP driver was originally designed for using Prism cards for access point applications (and can still be used for that). It is also a fine alternative to orinoco and wlan_ng for Prism-based devices.
How do I configure the client?
man iwconfig will list the entire command set for the wireless tools package. Note that not all cards support all functions such as limiting transmit power or promiscuous mode. Use these commands to change the wireless parameters on your device such as WEP key, mode and SSID.
How do I make the configuration changes permanent?
Using wireless tools will change the card settings, but they'll be lost on reboot unless you set them in a configuration file. The exact location will vary by distro, but two examples:
Slackware - /etc/pcmcia/wireless.opts
Red Hat - /etc/sysconfig/network-scripts/ifcfg-eth0
Can I make my own wireless access point?
Tools & Links
KwiFiManager - a task bar utility for KDE that mimics the ORiNOCO client utility. Works with wireless tools.
Kismet - NetStumbler on steroids.
Airsnort - Wireless Sniffer with a simple GUI.
Linux Wireless Page - Still the best and should be your first stop.
LinuxQuestions Hardware Compatibility List - Real folks posting real experiences.
FreeRADIUS - Using Linux to secure wireless networks.
EAP Wireless HOWTO
Cisco Whitepaper on EAP-TLS
Wireless On Linux Guides