Slackware Wireless Tutorial

In this tutorial I will give some guidelines to getting wireless up and running in Slackware (in my case, version 12.2).

I say "guidelines" because I don't entirely understand the Slackware system and are more familiar with Debian; but wanted to try something new!

My particular card is an Engenius EPI-3601S and it uses the Atheros 5001X+ chipset (chip number AR5211). A particularly nice feature of this card is its 600mW power rating, which is far beyond that of big-box store cards by manufacturers like Linksys, D-Link, etc.

The driver for this chipset is actively developed by the Mad-WiFi Project and is known as the 'ath5k' driver.

Okay, now for the good stuff:

Once your card is installed into the PCI or PCI-e bus, and the machine is booted, ensure the system can recognize your card. Take note that in all my output from commands I have just shown the relevant information.

# lspci

03:00.0 Ethernet controller: Atheros Communications Inc. Atheros AR5001X+ Wireless Network Adapter (rev 01)

The system *should* load the ath5k driver at boot, and you can verify this by performing "# lsmod | grep ath5k", however if it does not you can easily insert it yourself with the command "# modprobe ath5k". If the driver is not found, you will have to seek other online resources to compile it yourself, and then refer back to this tutorial once you've done so.

There are three primary configuration files that need to be configured before we can use our card, and they are:

/etc/rc.d/rc.inet1.conf

/etc/rc.d/rc.wireless.conf

/etc/wpa_supplicant.conf

First, I must mention that I find the rc.wireless.conf to not be of much value. It is more of a "global" wireless settings file that all wireless interfaces would inherit parameters from. While this might be useful in certain apps, I personally think it makes more sense to specify the wireless settings in rc.inet1.conf on a per-interface basis, just as you would for wired ethX connections. This allows you to specify unique settings for each wireless interface you may have on your system (useful if you have more than one). Thus, in my rc.wireless.conf I deleted all the provided examples and simply have the below.

# cat /etc/rc.d/rc.wireless.conf

VERBOSE=1

case "$HWADDR" in

# Generic example (decribe all possible settings)
*)
#INFO="Fill with your own settings..."
# ESSID (extended network name) : My Network, any
#ESSID=""
# NWID/Domain (cell identifier) : 89AB, 100, off
#NWID=""
# Operation mode : Ad-Hoc, Managed, Master, Repeater, Secondary, auto
#MODE=""
# Frequency or channel : 1, 2, 3 (channel) ; 2.422G, 2.46G (frequency)
#FREQ=""
#CHANNEL=""
# Sensitivity (cell size + roaming speed) : 1, 2, 3 ; -70 (dBm)
#SENS=""
# Bit rate : auto, 1M, 11M
#RATE=""
# Encryption key : 4567-89AB-CD, s:password
#KEY=""
# RTS threshold : off, 500
#RTS=""
# Fragmentation threshold : off, 1000
#FRAG=""
# Other iwconfig parameters : power off, ap 01:23:45:67:89:AB
#IWCONFIG=""
# iwspy parameters : + 01:23:45:67:89:AB
#IWSPY=""
# iwpriv parameters : set_port 2, set_histo 50 60
#IWPRIV=""
;;
esac

Everything is commented out in the case statement, but I left the parameter names just incase down the road I ever need to use rc.wireless.conf.

The next step is the configuration of rc.inet1.conf and wpa_supplicant.conf.

rc.inet1.conf will allow us to specify the settings of each wired/wireless interface that is recognized by the output of '# ip link'

The relevant (wireless) part of my rc.inet1.conf is as such:

# cat /etc/rc.d/rc.inet1.conf

IFNAME[4]="wlan0" <---- The name of the interface as it should be reported by ifconfig and iwconfig
IPADDR[4]="192.168.1.48" <--- I use static IP addressing, and this has been set-up in advance on my router (Will explain dhcp later)
NETMASK[4]="255.255.255.0" <--- The netmask my router uses... should be identical to that of your working wired connections
USE_DHCP[4]="no" <---- May not be required if IPADDR is specificied, but included anyways
WLAN_RATE[4]="54M auto" <--- May not be required on all cards, but mine defaulted to 12M without specifiying!
WLAN_WPA[4]="wpa_supplicant" <--- Tells rc.inet1 that it needs to refer to the WAP-PSK connection settings in etc/wpa_supplicant
WLAN_WPADRIVER[4]="wext" <--- The WPA-PSK driver to use when calling wpa_supplicant commands

The above should be sufficient for the majority of setups. If you don't use static IP addressing on your AP, then comment out the IPADDR line and set the USE_DHCP line to "yes". It also doesn't hurt to read through the other lines that are commented out in the example; there may be something that you find of value to adjust, but it is better to start with a minimal configuation and at least get somethign working first before piling on exotic options. Make sure that if you specify WLAN_RATE you put "54M auto" and not just "54M"! For me this seemed to crash the whole process of bringing up the interface and I spent considerable time pulling out my hair figuring out what the issue was.

My advice is to use wpa_supplicant even if your AP does not use a key for access. The default wpa_supplicant.conf provides two network examples. The top (first) one is for an AP that requires a key and the second one is for an AP that does not (free public APs). I will focus my attention on the one that requires a key. Assuming your AP requires a key (most likely WPA-PSK w/ TKIP encryption), you first need to run '# wpa_passphrase essid-of-your-AP passphrase-of-your-AP' to get a hexadecimal encryption key to be manually inserted into your wpa_supplicant.conf.

ASIDE: If you are clueless about some of the settings and capabilities of your AP, I suggest running '# iwlist wlan0 scan'. If you get a message that the network is down, first type '# ifconfig wlan0 up'. This will show you all the APs that your card has detected, along with the essids, the encryption (if any) that they use, and the supported bit rates of that AP.

An example output of my personal wpa_supplicant.conf (edit, of course, for security reasons):

# cat /etc/wpa_supplicant.conf

# This line enables the use of wpa_cli which is used by rc.wireless
# if possible (to check for successful association)
ctrl_interface=/var/run/wpa_supplicant
# By default, only root (group 0) may use wpa_cli
ctrl_interface_group=wheel
eapol_version=1
ap_scan=1
fast_reauth=1

# WPA protected network, supply your own ESSID and WPAPSK here:
network={
scan_ssid=1
ssid="your-ssid-goes-here"
proto=WPA
key_mgmt=WPA-PSK
pairwise=CCMP TKIP
#group=CCMP TKIP WEP104 WEP40
#psk below was made with wpa_passphrase
psk=abcdef12345abcdef12345abcdef12345abcdef12345abcdef

}

That's about it! You can either do a full system reboot or run the rc.inet1 script as root. If you want to just run the script on the wlan0 interface, the proper command is 'rc.inet1 wlan0_start'.

 Supplemental Information