Wifi Connectivity

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This page is part of the XO Support FAQ.     Support Index | Print This Page
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If you want to connect to the internet, and you are using Sugar, see Connecting to the Internet page at the Sugar Labs Wiki.

See also Give Me the Internet, Please for 8.2.0.

Overview

XO laptops were designed for children in developing nations, where it was faster and less expensive to introduce wireless networks rather than traditional cabled infrastructure. The XO laptop was designed to use these networks, or to connect with other XO laptops using a mesh network or an ad-hoc network.

Hidden Networks

A wireless network may be hidden. This does not make the network more secure, but it is occasionally done.

Unlike normal networks, a hidden network will not be visible in the Neighborhood View.

To connect to a hidden network, follow the steps in the section below that corresponds to the operating system version on the XO.

10.1.3 and 11.2.0

Using a hidden network in GNOME is straightforward; left-click on the wireless icon and select "Connect to Hidden Wireless Network...".

Using a hidden network in Sugar is far more complex. You must switch to GNOME, reconfigure Network Manager, restart Network Manager, connect to the hidden network, mark the network available to all users, then switch back to Sugar.

The procedure in detail is:

  • Use "My Settings" to switch to GNOME,
  • Edit the file /etc/NetworkManager/nm-system-settings.conf
sudo gedit /etc/NetworkManager/nm-system-settings.conf
  • Change plugins=ifcfg-rh to plugins=keyfile, then save,
  • Restart Network Manager,
sudo /etc/init.d/NetworkManager restart
  • Locate the wireless icon, it should be to the left of the date and time on the top right of the screen,
  • Left-click on the wireless icon and select "Connect to Hidden Wireless Network...", and a window with that title will appear,
  • Enter the hidden network name and click on "Connect", and the wireless LED should flicker and then glow,
  • Verify you can reach the internet using Firefox or some other GNOME application,
  • Right-click on the wireless icon and select "Edit connections...'", and a "Network Connections" window will appear,
  • Click on the "Wireless" tab,
  • Click on the hidden network entry you created, then on "Edit", and an "Editing hidden" window will appear,
  • Turn on "Connect automatically", if it isn't already, (near the top of the window),
  • Turn on "Available to all users", (near the bottom of the window), and;
  • Click "Apply",
  • Switch back to Sugar.

The connection to the hidden network will be made automatically whenever the laptop is booted, regardless of whether Sugar or GNOME is running. The connection will remain active over restart of Sugar or GNOME.

8.2.1

Every time the laptop is started up, a hidden network must be manually added through the Terminal Activity: 

su -l
/etc/init.d/NetworkManager stop
/sbin/iwconfig eth0 mode managed essid myhiddennetwork
/sbin/dhclient eth0
exit

After this, Neighborhood View should show any other XOs on the same access point, and Browse should be able to reach the internet. A symbol for the access point will not be displayed.

Special Considerations

Wireless Access Point Setup

The OLPC Support Team had been gathering notes and configuration tips for various Wireless Access Point (WAP) connectivity. We were working to resolve minor compatibility issues with various Wireless Access points, but not any more.

Some key setup considerations for your Wireless Access Point are:

  • A single channel should be selected, not "Automatic"
  • Preferred Channels are 1, 6, and 11
  • The wireless network mode should be "Mixed" or "Wireless-G", not "Disabled" or "Other"
  • If Wireless MAC Filtering is enabled, the MAC address for the XO must be entered
  • The latest Firmware should be loaded on your access point
  • Make sure that there are only alphanumeric characters and no spaces in your network name, or SSID.

Channel

With 802.11b or 802.11g, use channel 1, 6 or 11 in the US or Canada. Use of any other channels will degrade your own wireless signal and that of others.

Similarly, the mesh networking and adhoc network between XO laptops is restricted to work only on channels 1, 6 or 11.

Security

What is the difference between a key and a passphrase?

When you try to connect to a secured (encrypted) network your XO has to send an encryption key to the access point. This key is derived from the passphrase you chose when you configured your access point (and also from the ESSID, if you are using WPA).

So, the passphase is the long password that is relatively easy to remember while the key looks like a random sequence of characters. The length of the key varies depending on the type of security and it is usually represented in its Hex form, meaning that it will be formed by a sequence of digits and letters from A to F.

With WEP, the conversion from passphrase to key is not standardized and therefore is different on various companies' access points. Also, the WEP example below is only for 104/128 bit WEP. It will not work on 40/56 bit WEP. For these and other reasons, use WPA if you can.

Here is one example, for WEP:

Here is another example, for WPA-PSK:

  • Key length: 256 bits
  • PassPhrase: MyPassPhrase
  • ESSID: MyEssid
  • Resulting key (64 characters long): c3044f3fbd077e236d12f0b1f9d7761e0e6de266783d843d76edf1da3131bff6
  • Converted using: http://www.xs4all.nl/~rjoris/wpapsk.html

WEP Security

WEP Security is built in to the XO.

If you have a WEP pre-shared key, it can be set within the Terminal Activity: 

su -l
/sbin/iwconfig eth0 key 381E966F1EAE4140F83D30C201
exit
  • /sbin/iwconfig sets the WEP key in the XO to match your WAP (of course, substitute your WEP pre-shared key for the 381E966F1EAE4140F83D30C201 in the above example).

WPA Security

WPA security requires extra steps.

The XO is known to be unable to connect to certain Access Points when those networks are configured with WPA security. It is unfortunately not possible to classify such access points without detailed technical diagnosis on a case-by-case basis. See <trac>7825</trac> for the technical details. If you are unable to connect to your WPA access point, you may consider switching to WPA2 (RSN) which is not affected by this flaw.

MAC Filtering

Wireless MAC Filtering is a security measure that restricts access to the WAP by MAC Address. Every computer or other peripheral has a unique HEX address assigned at the time of manufacture.

The MAC address for the XO is displayed using the Linux command ifconfig.

Note: You will find ifconfig in the /sbin directory, which is not in the default path. Type /sbin/ifconfig

Troubleshooting Guide

The Wifi Troubleshooting Guide provides a step by step checklist to review prior to contacting Technical Support.

See also

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