After my installation of Arch Linux I had some trouble using my wifi card which was working while I was running the live CD. What was strange was that the card would show up in iwconfig and ifconfig -a but not ifconfig It turns out I needed to install the wireless drivers and here’s how I did it:
ifconfig wlan0 up
SIOCSIFFLAGS: No such file or directory
dhcpcd: version .2.2 starting
dhcpcd: wlan0: up_interface: No such file or directory
dhcpcd: wlan0: waiting for carrier
dhcpcd: timed out
Find out what card you are using:
lspci | grep Network
04:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG [Golan] Network Connection (rev 02)
If you don’t have access to a wired connection, check out this guide to installing packages from the Arch Linux cd.
Once you get it up and running, updating via pacman (-Syu) will probably replace these drivers for newer ones which continue to work.