Wireless access using linux

Introduction

Setting up a linux machine to use the university wifi network is non trivial. I suggest getting a friendly sysadmin involved. With the help of Andrew Cantell I finally have wifi access from linux. Here are a few things I learnt in the process of getting it to work.

Bringing the ethernet interface up (or down)

If you start fiddling with your ethernet cable, pulling it out or plugging it back in after your computer has booted up you may need to restart your ethernet interface. Rather than rebooting try the following to bring it up:

sudo ifup eth0

To bring it down use:

sudo ifdown eth0

Configuring the wireless interface

The following two files are important

• ~/.wpa/wpa_supplicant.conf
• /etc/network/infterfaces

My wpa_supplicant.conf file looks like this:

# IEEE 802.1X with dynamic WEP keys using EAP-PEAP/MSCHAPv2


ctrl_interface=/var/run/wpa_supplicant


  eapol_version=1
  ap_scan=1
  fast_reauth=1

network={
        ssid="uoa"
        scan_ssid=1
        key_mgmt=IEEE8021X
        eap=PEAP
        phase2="auth=MSCHAPV2"
        identity="EC\UPI_HERE"
        password="PASSWORD_HERE"
        ca_cert="/etc/ssl/certs/Verisign_Class_3_Public_Primary_Certification_Authority_-_G2.pem"
        ca_cert2="/etc/ssl/certs/Verisign_Class_3_Public_Primary_Certification_Authority_-_G2.pem"
}

You will need to insert your upi in place of UPI_HERE and your network password in place of PASSWORD_HERE.

My interfaces file looks like this:

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet dhcp

iface ath0 inet dhcp
        wpa-conf /home/pbie003/.wpa/wpa_supplicant.conf

Bringing the wireless interface up (or down)

To bring up the wireless interface type:

sudo ifup ath0

This command will poll your connection (often 5 or 6 times before it connects). In my experience, if it doesn't work the first time you run it, try running the command again. If it fails after the second attempt at exectution try bring the interface down and then back up again:

sudo ifdown ath0
sudo ifup ath0

Restarting your network

If things seem screwy you can try to restart you network software. For example if you unplug your ethernet cable while your machine is running (or plug it back in) you may need to restart your networking software to detect the connection. You can probably do this with the ifup command but if that fails try the following command:

sudo /etc/init.d/networking restart

Testing

The first thing to test is you can ping other machines. Try:

ping www.google.co.nz

Or you could try pinging bioeng10.

If that doesn't work it may be because your network ip address lookup isn't working. Try:

nslookup www.google.co.nz

If this command works and spits back an ip address this is a good sign.

Note that to use firefox (or your browser of choice) you may need to change your preferences for your networking settings from the usual to something like "Direct connection".