Brief WPA Introduction

• Wi-Fi Protected Access (WPA) is a family of encryption methods used when connecting to a wireless access point. It is based on the technology that is used in Wired Equivalent Privacy (WEP) but provides stronger security. For more information on the subject you can see the [http://en.wikipedia.org/wiki/Wi-Fi_Protected_Access WPA] entry on Wikipedia.

Hardware

You can use sudo iwconfig to check that you have your wireless device working. Most of the time this should be the case, but sometimes the drivers (kernel modules) fight, and the wrong one wins---for example, Prism 2 cards supported by hostap may instead end up using the orinoco driver, which won't work properly. Add incorrect modules to /etc/modprobe.d/blacklist.

Network Manager

For Ubuntu 6.06 LTS (Dapper) or later, there should be a Network Manager icon in the GNOME panel, which looks like a couple of dots. Right click the Network Manager icon to enable the network if necessary. Next, left click on the Network Manager icon and choose "Connect to other wireless network". Then, enter "YOUR-SSID" for the network name and choose your type "WPA ENTERPRISE" or "WPA PERSONAL" etc, etc ... for wireless security. Enter the password in the password text entry box. Click connect to attempt a connection.

If you do not see a network icon near your power information, or if WEP is your only encryption choice for network configuration, you may need to install Network Manager. For Ubuntu users:

sudo apt-get install network-manager-gnome

Kubuntu users should install the KDE version:

sudo apt-get install network-manager-kde

Or for Kubuntu 6.06:

sudo apt-get install knetworkmanager

After installing the package, logout and log back in (or re-start) and Network Manager should appear.

Avoiding password nagging

Gnome Network Manager bugs for the keyring password on login, so install pam-keyring to get around that.

Either use the unofficial debian package found at: ubuntuforums.org http://ubuntuforums.org/attachment.php?attachmentid=11818&d=1151394726 , or install from source. (Warning: be careful about install from unauthenticated sources; it's a little safer to build from source---see the instructions below.)

Here is the link to get the source package * http://www.hekanetworks.com/pam_keyring/ * http://www.hekanetworks.com/opensource/pam_keyring/

You may need to get a few packages in addition to build-essential to complete the build.

Using Synaptic get: * libpam0g-dev * libgnome-keyring-dev * libglib2.0-dev * autotools-dev * libtool

Here are the steps to install: # Download # Unzip to folder (e.g. ~/pam_keyring_tmp) # In Terminal:

cd ~/pam_keyring_tmp
./configure --prefix=/usr --libdir=/lib
make
sudo make install
cd /etc/pam.d
sudo gedit gdm

To look like:

#%PAM-1.0
auth    requisite       pam_nologin.so
auth    required        pam_env.so
@include common-auth
@include common-account
session required        pam_limits.so
@include common-session
@include common-password
## Added for pam-keyring so that NetworkManager doesn't ask for Keyring password.
## Please note that keyringpassword and login password must be the same.
auth optional pam_keyring.so try_first_pass
session optional pam_keyring.so

Reboot your computer, log out and in again, or hit ctl-alt-backspace to restart X.

As I mentioned in the comments in gdm file, this relies on having the password of the default keyring the same as your login password. ENJOY!

Original instructions from: http://ubuntuforums.org/showthread.php?t=187874 and http://ubuntuforums.org/showthread.php?p=1619571 and http://ubuntuforums.org/showthread.php?t=192281

If your wireless card is based on the rt2500 chipset, do not follow these instructions, as WPA has to be configured as described in ["WifiDocs/Driver/RalinkRT2500"].

WPA Supplicant

Before proceeding any further, it might be worthwhile to check whether your Wi-Fi Card is supported. [http://hostap.epitest.fi/wpa_supplicant/ wpa_supplicant website] This will save you lots of time and frustration.

Configuring {{{wpa_supplicant}}}

WPA supplicant provides WPA support, as well as automatic selection of the best available configured access point. WPA supplicant should already be installed in Dapper and later. Otherwise, install it:

•   sudo apt-get install wpasupplicant

You then need to configure it.

Edit /etc/wpa_supplicant.conf to include your network. The info to include can be generated with wpa_passphrase (although this is optional, it saves the supplicant having to generate the preshared key (PSK) each time it is started):

attachment:IconsPage/IconExample48.png

•   dennis@mirage:~$ wpa_passphrase NetworkEssid
    # reading passphrase from stdin
    TextPassphrase
    network={
          ssid="NetworkEssid"
          #psk="TextPassphrase"
          psk=945609a382413e64d57daef00eb5fab3ae228716e1e440981c004bc61dccc98c
    }

Requiring wpa_passphrase to prompt for the passphrase, rather than providing it as a command line argument, prevents the phrase from being stored insecurely in your shell's history.

Then add the following to the end of /etc/wpa_supplicant.conf:

•   network={
          ssid="NetworkEssid"
          scan_ssid=1 # only needed if your access point uses a hidden ssid
          proto=WPA
          key_mgmt=WPA-PSK
          psk=945609a382413e64d57daef00eb5fab3ae228716e1e440981c004bc61dccc98c
    }

You may have to specify proto=WPA and key_mgmt=WPA-PSK, but wpa_supplicant can usually autodetect them correctly.

Testing the configuration

Next we test the WPA supplicant. To do this you first determine which driver you have. The supported drivers are visible by running wpa_supplicant -h. In this example I assume the madwifi driver. You also need to know the name of your card's interface. In this example I assume ath0.

Now simply start wpa_supplicant for testing:

•   sudo wpa_supplicant -iath0 -c/etc/wpa_supplicant.conf -Dmadwifi -w

You should see something like the following, but more verbose (if you get a different result, append -dd to the above command line and ask someone on #ubuntu for help): attachment:IconsPage/IconExample48.png

•   Trying to associate with 00:ff:00:1e:a7:7d (SSID='NetworkEssid' freq=0 MHz)
    Associated with 00:ff:00:1e:a7:7d
    WPA: Key negotiation completed with 00:ff:00:1e:a7:7d [PTK=TKIP GTK=TKIP]

Now interrupt wpa_supplicant with <ctrl> C

Final installation (Ubuntu 6.10 (Edgy))

Telling Ubuntu Edgy to use WPA supplicant is pleasingly easy.

First find the interface in /etc/network/interfaces. It should look like this:

auto ath0
iface ath0 inet dhcp

Now add these two lines immediately below that:

wpa-driver madwifi
wpa-conf /etc/wpa_supplicant.conf

Where, as above, you have to use your driver and interface in place of the example madwifi and ath0. That's it! Now when you ifup/ifdown the interface (of Ubuntu does it for you on boot/shutdown), wpa_supplicant will be correctly started and stopped.

Final installation (older versions)

attachment:IconsPage/IconExample48.png

• Once wpa_supplicant works, you should edit /etc/network/interfaces to include wpa_supplicant. If prior to all of this, your /etc/network/interfaces looks like:

    auto ath0
    iface ath0 inet dhcp

  Simply change it to look like:

    auto ath0
    iface ath0 inet dhcp
    pre-up /etc/init.d/wpasupplicant start
    pre-up sleep 5

This looks like an optional step, too. As of 0.4.7-0ubuntu3, the /etc/network/if-pre-up.d/wpasupplicant script will take care of this step automatically. - 20060107 DaniloPiazzalunga

It is indeed optional and only relevant for Breezy systems. I made the change in Dapper's package. - 20060110 [DanielTChen]

For an alternative more detailed way to configure /etc/network/interfaces to work with wpa_supplicant 0.4.8-3ubuntu1.1 try [http://svn.debian.org/wsvn/pkg-wpa/trunk/wpasupplicant/debian/README.modes?op=file&rev=0&sc=0] - particularly if you want to set up a static IP address, which Network Manager doesn't currently support very well

• Finally, edit /etc/default/wpasupplicant to enable wpa_supplicant and provide its command line options. For our example setup, this would be:

    # Useful flags:
    #  -D <driver>          Wireless drive, typically optional.
    #  -i <ifname>          Interface
    #  -c <config file>     Configuration file
    #  -d                   Debugging (-dd for more)
    #  -w                   Wait for interface to come up
  
    # See the manual page wpa_supplicant(1) for more options and information.
  
    ENABLED=1
    OPTIONS="-iath0 -c/etc/wpa_supplicant.conf -Dmadwifi -w"

Note that in Dapper, because of a newer kernel (2.6.15) and a newer wpasupplicant package (0.4.7), your wireless driver may already support the kernel's wireless extensions interface. Please consult the README.Debian. - 20060110 [DanielTChen]

I placed the "ENABLED=1" setting directly above the "OPTIONS" setting; it was easy to miss that setting when it was above the comment section in the file. - 20060129 [Scott]

If you have an ipw2200 wirless card and a kernel 2.6.16 or newer, you maybe have to use "wext" driver instead of "ipw"

=== Integration with DHCP ====

Note that the instructions below are deprecated. The changes that I made in Dapper's wpasupplicant package already take care of this case. [DanielTChen]

• If you want your wireless card to aquire a new IP address using DHCP when wpa_supplicant associates with an access point, use the wpa_cli utility as documented in the wpa_supplicant [http://hostap.epitest.fi/cgi-bin/viewcvs.cgi/*checkout*/hostap/wpa_supplicant/README?rev=HEAD&content-type=text/plain README]:

    wpa_cli can used to run external programs whenever wpa_supplicant
    connects or disconnects from a network. This can be used, e.g., to
    update network configuration and/or trigget DHCP client to update IP
    addresses, etc.

  The wpa_cli utility can automatically execute a script whenever wpa_supplicant connects or disconnects from an access point. For this, use the -a switch like so:

    wpa_cli -a<my-script>

  The script will be invoked like this:

    my-script $IF $CONN

  Where $IF is the interface (eth0, ath0, etc), and $CONN is the event - either "CONNECTED" or "DISCONNECTED".

attachment:IconsPage/IconExample48.png

• The simplest thing to do is write a script that invokes ifup or ifdown. I've put it in /sbin/wpa_action:

    #! /bin/bash
  
    IFNAME=$1
    CMD=$2
  
    if [ "$CMD" == "CONNECTED" ]; then
      SSID=`wpa_cli -i$IFNAME status | grep ^ssid= | cut -f2- -d=`
      logger "WiFi: Connecting `$IFNAME' to network `$SSID'"
      ifup $IFNAME
    elif [ "$CMD" == "DISCONNECTED" ]; then
      logger "WiFi: Disconnecting `$IFNAME`"
      ifdown $IFNAME
    fi

  Then, edit /etc/init.d/wpasupplicant to run wpa_cli appropriately. Look for these lines:

    case "$1" in
          start)
                  echo -n "Starting wpa_supplicant: "
                  start-stop-daemon --start --name $PNAME
                          --oknodo --startas $DAEMON -- -B $OPTIONS
                  echo "done."
                  ;;
          stop)

  Insert a sleep and wpa_cli call below the start-stop-daemon call:

     case "$1" in
          start)
                  echo -n "Starting wpa_supplicant: "
                  start-stop-daemon --start --name $PNAME
                          --oknodo --startas $DAEMON -- -B $OPTIONS
                  sleep 1
                  wpa_cli -a/sbin/wpa_action -B
                  echo "done."
                  ;;
          stop)

  If you are using DHCP exclusively to configure your wireless interface, then make sure you have this line for your wireless interface in /etc/network/interfaces:

    iface eth0 inet dhcp

  Where "eth0" is your wireless interface. And you'll want to make sure that your computer doesn't try to automatically start the interface up without an associated AP, so remove your wireless interface from the 'auto' line in /etc/network/interfaces:

    auto lo eth0 eth1

  So it becomes

    auto lo eth1

  Listing only those interfaces that you want to configure on startup. (Obviously, your 'auto' line will look different, depending on what network interfaces you have on your system.) Now, whenever you associate with a new wireless access point, your wireless interface will have an IP automatically configured and you'll be fully connected to the network. (YAY!)

GUI for WPA_Supplicant

A Qt-based application is available that lets you monitor what wpa_supplicant is up to: [http://packages.ubuntu.com/dapper/net/wpagui]

You will need to run it via gksudo wpa_gui so that it can talk to the WPA daemon.

Troubleshooting intermittant disconnects

This can be caused by Network Manager. Apparently when Network Manager scans for APs, wpa_supplicant will disconnect. Disabling Network Manager allows WPA to work, but you loose the NM function of automatic connections.

Links and Resources

[http://en.wikipedia.org/wiki/Wi-Fi_Protected_Access WPA] [http://hostap.epitest.fi/wpa_supplicant/ wpa_supplicant website]

Comments

Pretty sure "network management framework (GNOME Frontend)" is what made WPA "just work" - the problem is I have followed 3 or 4 sets of instructions, so I can't be sure that the one package is all you need - but it sure seems it is a good place to start. If someone can confirm this, fix this entry (or e-mail CarlKarsten and I'll fix it.) So try this: First disable the System, Administration, Networking - select the/all interface - Properties, uncheck "Enable this connection" (so that the next step can take over managing it.), OK, OK.

sudo apt-get install network-manager-gnome

look for a new icon in the upper left - click it - you should see a list of ESSID's (wireless network names)

Using /etc/rcS.d for boot

This is for launching wpa_supplicant as a background daemon on boot in Ubuntu 6.06 LTS (Dapper)

You need to have wpa_supplicant.conf created and know how to launch wpa_supplicant from the command line

• I tried the examples above and the man 8 page for wpa_supplicant examples, but could not get it to launch automatically on boot. This approach seems very straightforward. If you can run your launch script manually, it will run on boot just the same. The other methods seem very difficult editing the system files.

Work around for booting with /etc/init.d and /etc/rcS.d

Create a simple shell script in /etc/init.d that launches the wpa_supplicant as a background daemon:

/etc/init.d/wpa_launch.sh
    #!/bin/bash
    /sbin/wpa_supplicant -Bw -iath1 -Dmadwifi -c/etc/wpa_supplicant/wpa_supplicant.conf

Create a symbolic link in /etc/rcS.d that points to the launch script:

ln -s /etc/rcS.d/S42wpa_launch -> /etc/init.d/wpa_launch.sh

Are there potential disadvantages of this method? Please post comments here.

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