Linux Unwired [Electronic resources] نسخه متنی

2.1 Quick Start

If you haven't purchased a Wi-Fi
card yet, and are happy with 802.11b (about 5.5 Mbps real-world speed
versus about 20 for 802.11a or g), pick up either a
Lucent/Agere/Avaya/Proxim Orinoco Silver or Orinoco Gold (see Section 2.2.1.2 later in this chapter). If
you've purchased a different card, it may work out
of the box with Linux. But if it doesn't, the rest
of this chapter describes chipsets and drivers in enough detail for
you to find your way. Unfortunately, the orinoco_cs driver does not
support monitor mode, which passive monitoring tools such as Kismet
require. See Chapter 3 for information on
monitor mode and available patches for orinoco_cs. If you want to use
monitor mode with an unpatched driver, we suggest that you use a
Prism or Atheros-based card.

When you install Linux for the first time, load the modules for all the built-in network interfaces, especially any wired Ethernet adapters you might use in the future to avoid a particular situation where your Wi-Fi card is assigned and configured as eth0 during installation, but the system later detects the onboard Ethernet and assigns it to eth0 (bumping up your Wi-Fi adapter to eth1 and messing up the configuration files that think eth0 is your Wi-Fi adapter).

You must install the wireless tools package, which is described in
Section 2.3.4 later in this chapter.
The name of this package in all the Linux distributions in the
following list is wireless-tools.

We tested the Proxim Orinoco Classic Gold (pictured in Figure 2-1) with several Linux distributions on an IBM
ThinkPad A20m with onboard Ethernet (eth0), and this is what we
found:

Debian 3.0r1

We used disk 5 (kernel 2.4.18-bf2.4) to boot the installer and
installed the base system using disk 1. During installation, the card
was recognized and configured properly using orinoco_cs and the eth1
adapter.

SuSE 9.0

We used the free download version of SuSE 9.0 and installed
everything over FTP. The installer did not automatically detect the
card, so we had to use wired Ethernet for the installation. However,
when we booted the system for the first time, SuSE found the card and
configured it automatically using the orinoco_cs driver as wlan0 (the
default for orinoco_cs would be to use eth1).

Mandrake 9.2

The card was automatically detected during installation. We
configured it by clicking Configure under Network & Internet when
the installer reached the summary screen. Mandrake offers advanced
options, including SSID (WIRELESS_ESSID) and WEP key
(WIRELESS_ENC_KEY). Mandrake used orinoco_cs and the eth1 adapter for
this card.

RedHat 9

The RedHat installer detected the card using the orinoco_cs driver
and set up the card as eth1. However, the card was not configured
correctly on first boot. We edited
/etc/sysconfig/network-scripts/ifcfg-eth1 and
set ONBOOT to no, which
corrected the problem. (Linux should always defer configuration of
PCMCIA adapters until the pcmcia
rc script runs.)

Gentoo 1.4

We performed a stage 3 install of Gentoo. After booting the
installer, we tried to start PCMCIA with /etc/init.d/pcmcia
start, but it insisted on loading the prism2_cs driver,
which did not work at all. However, after we installed Gentoo, built
a kernel with genkernel, and rebooted, Gentoo correctly loaded the
orinoco_cs driver (which saw the card as eth1).

Figure 2-1. The Orinoco Classic Gold card

If you're connecting to a network that uses WEP or one that doesn't broadcast its SSID, you may need to use the wireless tools, described later in this chapter, after installation is complete. However, if the Linux distribution supports advanced options (as does Mandrake 9.2), you should be able to connect to the network during the initial installation. For more information on using WEP with Linux, see Chapter 4.