Differences between revisions 50 and 51
Revision 50 as of 2013-11-15 10:42:51
Size: 10866
Editor: GeoffSimmons
Comment: sudo is not enabled by default on Debian systems.
Revision 51 as of 2013-12-11 19:33:44
Size: 11133
Editor: ?WebDawg
Comment:
Deletions are marked like this. Additions are marked like this.
Line 69: Line 69:

<!> You must remove network-manager to get wicd to work. Check to see if network-manager is installed and see if, after you installed the driver, your wireless is already working in the notification area of your desktop manager. You may already be good to go.

Translations: English - French - Italiano - Русский - 简体中文

How to use a WiFi interface

This page describes how to configure a WiFi interface on a Debian system, for use on a network.

Once your wireless device has an interface available (verifiable with iwconfig), it is required to be configured to access a network. If you do not have a wireless interface present, please refer to WiFi for information on providing a driver for your device.

Wireless network interface configuration can be performed using a connection manager (such as NetworkManager) or through Debian's /etc/network/interfaces file with a special purpose utility (such as wpa_supplicant). Examples of NetworkManager and wpa_supplicant configuration are described below.

<!> The WEP algorithm is insecure and deprecated by WPA. Use of WEP is not recommended and is not covered within this document.

NetworkManager

NetworkManager is configured through graphical interfaces, which are available for GNOME and KDE. Your wireless interface should not be referenced within Debian's /etc/network/interfaces file.

NetworkManager is also a front-end for wpa_supplicant.

GNOME

  1. Ensure your user account is a member of the netdev group.

  2. Install the network-manager-gnome package:

    $ su
    # apt-get update
    # apt-get install network-manager-gnome
  3. Log out of GNOME, then log back in to your system.
  4. A new applet (computer icon) will appear in the notification area / system tray. Left-click this icon to present the nm-applet pop-up menu.
  5. Neighboring wireless networks with a broadcasted SSID should be listed:
    • Click on the desired network's name.
    • If the network uses WPA encryption with a password (aka passphrase/pre-shared key), you will be prompted to enter it. After providing, click the "Connect" button.
    • The wireless network connection will be activated.
    If the desired network is not listed (e.g. SSID not broadcast/hidden):
    • Click "Connect to Other Wireless Network...".
    • Enter the network's SSID at "Network Name".
    • If encryption is used, select the method from the "Wireless Security" drop-down list (usually "WPA Personal" or "WPA2 Personal").
      • Enter the passphrase/pre-shared key at "Password".
    • Click the "Connect" button to activate the wireless network connection.

See the NetworkManager page for frequently asked questions, documentation and support references.

KDE

  1. Ensure your user account is a member of the netdev group.

  2. Install the network-manager-kde package:

    $ su
    # aptitude update
    # aptitude install network-manager-kde
  3. From the K Menu, select "Run Command". Enter "knetworkmanager" and click "Run".
  4. A new applet (wallplug/socket icon) will appear in the system tray. Right-click this icon to present the KNetworkManager pop-up menu.
  5. Neighboring wireless networks with a broadcasted SSID should be listed:
    • Click on the desired network's name.
    • If the network uses WPA encryption with a password (aka passphrase/pre-shared key), you will be prompted to enter it. After providing, click the "Connect" button.
    • The wireless network connection will be activated.
    If the desired network is not listed (e.g. SSID not broadcast/hidden):
    • Click "Connect to Other Wireless Network...".
    • Enter the network's name in "Name (ESSID)".
    • Tick "Use Encryption" if in use on the network.
      • Select the encryption method used (usually "WPA Personal").
      • Enter the passphrase/pre-shared key at "Password".
      • Select "WPA 1" or "WPA 2" for the protocol version, as used by the network.
    • Click the "Connect" button to activate the wireless network connection.

See the NetworkManager page for frequently asked questions, documentation and support references.

Wicd

<!> You must remove network-manager to get wicd to work. Check to see if network-manager is installed and see if, after you installed the driver, your wireless is already working in the notification area of your desktop manager. You may already be good to go.

wicd (Wireless Interface Connection Daemon) is a lightweight alternative to NetworkManager. It is environment-independent, making it suitable for all desktop environments, including GNOME, Xfce, LXDE, and Fluxbox. Like NetworkManager, wicd is configured via a graphical interface. Your wireless interface should not be referenced within Debian's /etc/network/interfaces file.

  1. Update the list of available packages and install the wicd package:

    $ su
    # aptitude update
    # aptitude install wicd
  2. Amend /etc/network/interfaces to contain only the following:

    # 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

    Note: as of wheezy it is fine to have your wireless interface in /etc/network/interfaces (it might even be required, not sure)

  3. If not already performed, add your regular user account to the netdev group and reload DBus:

    # adduser yourusername netdev
    # /etc/init.d/dbus reload
  4. Start the wicd daemon:

    # /etc/init.d/wicd start
  5. Start the wicd GUI with your regular user account: 

    # exit
    $ wicd-client -n

See also wicd frequently asked questions.

Command Line

Scan for available networks and get network details:

$ su
# iwlist scan

Now edit /etc/network/interfaces. The required configuration is much dependent on your particular setup. See the following example to get an idea of how it works:

# my wifi device
auto wlan0
iface wlan0 inet dhcp
        wireless-essid [ESSID]
        wireless-mode [MODE] 

For further information on available configuration options, see man interfaces, man wireless and /usr/share/doc/wireless-tools/README.Debian.

You can now bring your interface up and down with the usual ifup and ifdown commands. If you added auto wlan0 as in the example above, the interface should be brought up automatically during boot up.

wpa_supplicant

wpa_supplicant is a WPA client and IEEE 802.1X supplicant.

The wpasupplicant package provides wpa-* ifupdown options for /etc/network/interfaces. If these options are specified, wpa_supplicant is started in the background when your wireless interface is raised and stopped when brought down.

  • {i} GNOME and KDE users shouldn't configure wpa_supplicant manually. Use NetworkManager as explained above.

Before continuing, install the wpasupplicant package:

  • $ su
    # aptitude update
    # aptitude install wpasupplicant

WPA-PSK and WPA2-PSK

{i} Also known as "WPA Personal" and "WPA2 Personal" respectively.

  1. Restrict the permissions of /etc/network/interfaces, to prevent pre-shared key (PSK) disclosure:

    # chmod 0600 /etc/network/interfaces
  2. Open /etc/network/interfaces in a text editor:

    # sensible-editor /etc/network/interfaces
  3. Define appropriate stanzas for your wireless interface, along with the SSID and PSK. For example:

    auto wlan0
    iface wlan0 inet dhcp
        wpa-ssid mynetworkname
        wpa-psk mysecretpassphrase
    The "auto" stanza will bring your interface up at system startup. If not desired, remove or comment this line.
  4. Save the file and exit the editor.
  5. Bring your interface up. This will start wpa_supplicant as a background process.

    # ifup wlan0

Additional wpa-* options are described within /usr/share/doc/wpasupplicant/README.modes.gz. This should also be read if connecting to a network not broadcasting its SSID.

For general /etc/network/interfaces information, see the interfaces(5) man page.

WPA-EAP

For networks using EAP-TLS, you are required to establish a wpa_supplicant configuration file and provide the client-side certificate. An example WPA2-EAP configuration file can be found at /usr/share/doc/wpasupplicant/examples/wpa2-eap-ccmp.conf.

Once available, reference your configuration file in /etc/network/interfaces. For example:

  • auto wlan0
    iface wlan0 inet dhcp
        wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

More information can be found in the wpa_supplicant.conf(5) man page. A fully-commented wpa_supplicant configuration file example is at /usr/share/doc/wpasupplicant/README.wpa_supplicant.conf.gz.

Switching Connections

To switch between multiple distinct configurations:

  • GNOME users should use "Menu System > Administration > Network". (n.b. this doesn't work in etch)

  • Console users can

Security consideration

  1. Every member of a network can listen to other members' traffic (whether it's an unencrypted public hot-spot, or a WEP/WPA/WPA2, or LAN). Use SSL/TLS protocols (HTTPS, IMAPS...) or VPN to preserve your privacy.

  2. WEP is so insecure that it is basically equivalent to not using any encryption at all.
  3. WPA1 is deprecated. Use WPA2 instead.

  4. Make sure you use a strong pass-phrase.

Network security, see: http://www.aircrack-ng.org/doku.php?id=tutorial.

See Also


CategoryNetwork | CategoryWireless