Debian WiFi Setup

Manual HowTo

I previously posted on setting up Debian laptop WiFi, that was running Gnome desktop, which has a lot of in-built tools to assist in such matters. If you run a different desktop such as XFCE4, the process may not follow the steps outlined in the earlier post. You'll have to do a manual install and setup.

Its not hard, just takes a little work.

Set up WiFi with WPA2, more secure than WPA1 or the almost transparent WEP. WEP has close to zero security and can be cracked by any monkey carrying a banana.

Debian adds wireless-tools by default with desktop or laptop installation. Check if you have these components, using aptitude:

aptitude show wireless-tools

If they are not installed for whatever reason add them now.

aptitude install wireless-tools

There's a Debian WiFi Wiki but its a little confusing.

Procedure overview

1. Ensure WiFi is switched on!
2. Identify your WiFi card/on-board chip.
3. Download drivers
4. Install modules (modprobe iwl3495)
5. edit /etc/network/interfaces
6. Add SSID and password
7. Change file permissions 0600. Only root can see password/passphrase.
8. Add user to netdev group if not a member
9. Bring up interface
10. Add nameservers to resolv.conf

Steps in detail

1. Ensure WiFi is switched on!

My laptop (and maybe others) have a physical switch on the outside of the laptop case to switch on WiFi. Check if you have similar, then set it to 'on'. This gave me some trouble at one point.

2. Identify your WiFi device

Check your owner manual, manufacturer website, Google laptop specification online, or dmesg

dmesg | less

Scroll through till you find a reference to your WiFi chip . When you know your device go over to Debian Wiki a look at the list of devices and drivers. You should find your chip and the associated driver.

I have an Intel PRO/Wireless 3945 which uses iwl3945 driver.

3. Download driver

You need the wifi modules from Intel's WiFi Linux drivers site. The info on the site states the driver is included in all kernels from 2.6.24. My laptop runs the 2.6.32 kernel, but it still did not recognise the card and attach the driver. I had to download and add them manually.  Go to driver downloads and pull them down.

4. Install driver module

Unzip driver

gunzip iwlwifi-3945-ucode-15.32.2.9.tgz

The driver has two parts. Copy the driver to /lib/firmware

cp iwlwifi-3945* /lib/firmware

Install the driver

modprobe iwl3495

5. Edit /etc/network/interfaces

As root open /etc/network/interfaces in Emacs, Vi, or what editor you prefer and add the following:

auto wlan0
iface wlan0 inet dhcp
    wpa-ssid network-name (your network name goes here)
    wpa-psk passphrase (your password goes here)

6. Change permissions 0600

As a security measure, change permissions on the file.

chmod 0600 /etc/network/interfaces

Only root can see the password in the file.

7. Add user to netdev group

Check if you are a member of the netdev group

grep /etc/group

Output should display username

netdev:x:111:obama

If not a member, add yourself

adduser obama netdev

8. Bring up interface

Get the interface working

# ifup wlan0

9. Add nameservers

Add Google DNS servers to resolv.conf

emacs /etc/resolv.conf

nameserver 8.8.4.4

Save and quit.

10. Test Connections

Your home and dry. Or at least you should be. To test your connection, ping google or yahoo.

ping google.com

ping yahoo.com

On next reboot, wireless interface will start automatically.

Done!