Wireless Security - WPA2 PSK using wpa_supplicant howto

More and more wireless access networks are adopting 802.11i, the latest IEEE wireless network security standard. This howto explains how to configure and run a 802.11i supplicant (wpa_supplicant) with pre-shared key (PSK) authentication on your wireless network device.

wpa_supplicant is an EAP/WPA/WPA2 supplicant available for Linux, Windows and Unix systems. Windows binaries are available from the website. The following are two methods for installing wpa_supplicant under linux and FreeBSD.

Under debian compatible linux distributions, wpa_supplicant can be installed by typing

 sudo apt-get install wpasupplicant

Under FreeBSD

 cd  /usr/ports/security/wpa_supplicant/
 make install

or

 pkg_add -vrf wpa_supplicant

• Downloaded wpa_supplicant from here here

   wget http://hostap.epitest.fi/releases/wpa_supplicant-0.5.10.tar.gz

• Extract the archive

   tar xfz wpa_supplicant-0.5.10.tar.gz

• Create a .config file

   cp defconfig .config

• Build and install

  make 
  make install

Edit the wpa_supplicant configuration file (e.g. /etc/wpa_supplicant.conf), ant put the following

   network={
     ssid="YOUR-SSSID"
     psk=PSK
   }

• “PSK” is the PSK generated from the password shared with the wireless access point
• “YOUR-SSID” is the (B/E)SSID of the wireless access network.

To generate the wpa_supplicant.conf file, the wpa_passphrase tool can be used as follows.

wpa_passphrase YOUR-SSID PASSWORD

wpa_supplicant -B -i IFACE -Dwext -c /etc/wpa_supplicant.conf

Where IFACE is the name of your wireless interface.

• Check that you are associated

 iwconfig IFACE

• Get an IP address

 dhclient IFACE

In order to avoid typing all these commands each time you reboot or want to connect to your wireless network, you can (under linux) use the /etc/network/interfaces file to automatically handle network association and IP address acquisition. For this purpose, put the following in /etc/network/interfaces

 auto IFACE
 iface IFACE inet dhcp
     pre-up wpa_supplicant -Bw -Dwext -i IFACE -c/etc/wpa_supplicant.conf
     post-down killall -q wpa_supplicant

• hostapd RADIUS server configuration howto

Labels: howto, wireless, security