Slackware Linux Essentials
Prev	Chapter 5 Network Configuration	Next

5.5 Wireless

+ +

Wireless networking is still a relatively new thing in the world of computers, yet is +quickly catching on as more people begin to purchase laptops and want networking on the +go, without having to fool with some old twisted pair cable. This trend doesn't appear to +be slowing down. Unfortunately, wireless networking isn't yet as strongly supported in +Linux as traditional wired networking.

+ +

There are three basic steps to configuring an 802.11 wireless Ethernet card:

+ +

+
Hardware support for the wireless card
+
+
Configure the card to connect to a wireless access point
+
+
Configure the network
+

+ +

5.5.1 Hardware Support

+ +

Hardware support for a wireless card is provided through the kernel, either with a +module or built in to the kernel. Generally, most newer Ethernet cards are provided +through kernel modules, so you'll want to determine the appropriate kernel module and +load it through /etc/rc.d/rc.modules. netconfig may not detect your wireless card, so you'll probably need +to determine the card yourself. See http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/ for more +information on kernel drivers for various wireless cards.

+ +

5.5.2 Configure the Wireless +Settings

+ +

The vast majority of this work is done by iwconfig, so as +always read the man page for iwconfig if you need more +information.

+ +

First, you'll want to configure your wireless access point. Wireless access points +vary quite a bit in their terminology, and how to configure them, so you may need to +adjust a bit to accommodate your hardware. In general, you'll need at least the following +information:

+ +

+
The domain ID, or name of the network (called the ESSID by iwconfig)
+
+
The channel the WAP uses
+
+
The encryption settings, including any keys used (preferably in hexadecimal)
+

+ +

+ + + + + +

A NOTE ABOUT WEP. WEP is quit flawed, but it's much better than nothing. If you wish a +greater degree of security on your wireless network, you should investigate VPNs or +IPSec, both of which are beyond the scope of this document. You might also configure your +WAP not to advertise its domain ID/ ESSID. A thorough discussion of wireless policy is +beyond the scope of this section, but a quick Google search will turn up more than you +ever wanted to know.

+ +

Once you've gathered the above information, and assuming you've used modprobe to load the appropriate kernel driver, you can edit rc.wireless.conf and add your settings. The rc.wireless.conf file is a bit untidy. The least effort is to +modify the generic section with your ESSID and KEY, and CHANNEL if required by your card. +(Try not setting CHANNEL, and if it works, great; if not, set the CHANNEL as +appropriate.) If you're daring, you can modify the file so that only the necessary +variables are set. The variable names in rc.wireless.conf +correspond to the iwconfig parameters, and are read by rc.wireless and used in the appropriate iwconfig commands.

+ +

If you have your key in hexadecimal, that's ideal, since you can be fairly confident +that your WAP and iwconfig will agree on the key. If you only +have a string, you can't be sure how your WAP will translate that into a hexadecimal key, +so some guesswork may be needed (or get your WAP's key in hex).

+ +

Once you've modified rc.wireless.conf, run rc.wireless as root, then run rc.inet1, again as root. You can test +your wireless networking with standard testing tools such as ping, along with iwconfig. If you have a +wired interface you may wish to use ifconfig to turn those +interfaces off while you test your wireless networking to ensure there's no interference. +You may also want to test your changes through a reboot.

+ +

Now that you've seen how to edit /etc/rc.d/rc.wireless for +you default network, let's take a closer look at iwconfig and see how it all works. This +will teach you the quick and dirty way of setting up wifi for those times when you find +yourself at an Internet cafe, coffee shop, or any other wifi hot spot and wish to get +online.

+ +

The first step is to tell your wireless NIC what network to join. Make sure you +replace “eth0” with whatever network interface your +wireless card uses and change “mynetwork” to +the essid you wish to use. Yes, we know you're smarter than that. Next you'll have to +specify the encryption key (if any) used on your wireless network. Finally specify the +channel to use (if needed).

+ + + + + +

+# iwconfig eth0 essid "mynetwork"
+# iwconfig eth0 key XXXXXXXXXXXXXXXXXXXXXXXXXXX
+# iwconfig eth0 channel n
+

+ +

That should be all on the wireless end of things.

+ +

5.5.3 Configure the Network

+ +

This is done in the exact same way as wired networks. Simply refer to earlier sections +of this chapter.

Prev	Home	Next
PPP	Up	Network File Systems