Setting Up Wireless on a ThinkPad T60 (Arch Linux)

Posted by Ryan Coyner on September 6, 2008 under Arch Linux - 0 Comments

I had delayed setting up wireless on my laptop since I installed Arch Linux back in May. This wasn't an issue during the summer; wireless capabilities didn't mesh well with my work. I like to work in public places during the school year though so I finally got off my lazy ass and decided to set it up. Getting it working was easy - I simply followed the Arch Linux Wiki and configured my system to accomodate for my university's VPN.

Installing Modules & Packages

Having a wired ethernet connection made this process very easy. I first downloaded and installed the packages containing the wireless drivers and tools:

$ pacman -S madwifi madwifi-utils wireless_tools

Add the ath_pci module with modprobe:

$ modprobe ath_pci

Ensure that the module was loaded with lsmod:

$ lsmod |grep ath
ath_rate_sample        15872  1 
ath_pci               241848  0 
wlan                  222192  4 wlan_scan_sta,ath_rate_sample,ath_pci
ath_hal               250976  3 ath_rate_sample,ath_pci

Check to see if the driver has a usable wireless interface:

$ iwconfig
lo        no wireless extensions.

wifi0     no wireless extensions.

ath0      IEEE 802.11a  ESSID:""  Nickname:""
          Mode:Managed  Channel:0  Access Point: Not-Associated   
          Bit Rate:6 Mb/s   Tx-Power:16 dBm   Sensitivity=1/1  
          Retry:off   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=0/70  Signal level=-81 dBm  Noise level=-81 dBm
          Rx invalid nwid:69  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

eth0      no wireless extensions.

irda0     no wireless extensions.

tun0      no wireless extensions.

Specify which wireless network you want to connect to under /etc/rc.conf. The following is the configuration I use for my university:

ath0="dhcp"
wlan_ath0="ath0 essid gwireless"

Firing it Up

Scan for access points to make sure that you can connect:

$ iwlist ath0 scan |more
ath0      Scan completed :
          Cell 01 - Address: 00:18:74:48:52:60
                    ESSID:"gwireless"
                    Mode:Master
                    Frequency:2.412 GHz (Channel 1)
                    Quality=41/70  Signal level=-54 dBm  Noise level=-95 dBm
                    Encryption key:off
                    Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 6 Mb/s; 9 Mb/s
                              11 Mb/s; 12 Mb/s; 18 Mb/s; 24 Mb/s; 36 Mb/s
                              48 Mb/s; 54 Mb/s
                    Extra:bcn_int=100
...

Enable the interface with ifconfig:

$ ifconfig ath0 up

At this point you can use iwconfig to check whether you're connected or not.

And finally request an IP address using dhcpcd:

$ dhcpcd ath0

That was all I did to get connected.

VPN

If you need to connect to a VPN, you also need to install vpnc:

$ pacman -S vpnc

The configuration file is located under /etc/vpnc/default.conf. The following is a sample configuration:

IPSec gateway [ip address]
IPSec ID [vpn id]
IPSec secret [vpn password]
Xauth username [username]
Xauth password [password]

Simply run vpnc after you run dhcpcd to get wireless access.