Introduction

This page is a list of important config files used with wireless networking.

Files

/etc/network/interfaces

This file stores networking interface settings.

Network Manager cannot manage any interfaces that are named in this file. Network Manager has been the default way of managing network connections since Ubuntu 8.10 (Intrepid Ibex)

• If you are not currently using Network Manager and would like to, delete or comment out (with a # at the start of each line) your interfaces except for the two lines referring to lo (this is an internal loopback). Since Ubuntu 8.10, this file will look similar to this:

    # The loopback network interface
    auto lo
    iface lo inet loopback

• Do not use an auto stanza if you are using a PCMCIA deivce that you want to start automatically at boot-time. Add map <ath0> to the /etc/interfaces file. Your file should contain something similar to:

    #echo connects ath0 when device is hotplugged. using echo instead of grep allows any device to be brought up when hotplugged. Note this could cause a problem if a device is active and another one that is mapped is plugged in.
    mapping hotplug
            script echo
            map ath0

• Check your routers settings to ensure it can accept another connection.
• If you are running Ubuntu 8.04 (Hardy Heron) or earlier, you should have something similar to this:

  

    # The loopback network interface
    auto lo
    iface lo inet loopback
  
    # This is a list of hotpluggable network interfaces.
    # They will be activated automatically by the hotplug subsystem.
    # With lines # out these don't work. If they were removed this would hotplug only eth0 when cable is plugged in with active network
    #mapping hotplug
    #       script grep
    #       map eth0
  
    #echo connects ath0 when device is hotplugged. using echo instead of grep allows any device to be brought up when hotplugged. Note this could cause a problem if a device is active and another one that is mapped is plugged in.
    mapping hotplug
            script echo
            map ath0
  
    #interface of ath0 device with wep setting (not all these lines are required but show you options that may be needed)
    iface <ath0> inet dhcp
    wireless-essid xxxx
    wireless-key xxxxx
    wireless-key xxxx-xxxx-xx (in certain situations a - is needed after every 4 characters to work)
    wireless-key1 xxxx (add a number after key to specify key number to use.)
    wireless-defaultkey 1 (specifies which key is default)
    wireless-key s:xxx (add s: in front of key if ascii form)
    wireless-key XXXXXXXXXX open|restricted (if using shared/restricted setting add this line)
  
    auto <ath0>

Other Resources

• An /etc/network/interfaces sample - Part of LinuxPlanet's Connecting to a Wireless LAN with Linux, a tutorial by Carla Schroder.

• This file has a manual page. Type man interfaces in a terminal to view it.

• /usr/share/doc/ifupdown/examples/network-interfaces.gz. You can read through it with the cat command and then adding | less to the end of the command.

/etc/resolv.conf

This file stores Domain Name Server (DNS) settings including nameserver addresses, local domain names/search server addresses and some other advanced settings.

• This file has a manual page. Type man resolv.conf in a terminal to view it.

/etc/modules

This file lists some of the modules that will be loaded into the kernel at boot-time. If a driver won't load at boot, you can add it to this list so that it does.

/etc/modprobe/

To enable specific configuration options for a driver create an appropriate config file in this folder eg. config.conf or [drivername].conf and add the options you want to set in this file.

notes

With the release of Ubuntu 11.10 and kernel 3.x.x some wireless drivers now no longer need 11n_disable and 11n_disable50 options. Theses options may actually cause the driver to fail to load. Check the /etc/modprobe.d/ folder for config files that contain option reference to your driver, for example

options iwlagn 11n_disable=1 11n_disable50=1

These options can be found in config.conf or [drivername].conf file eg. intel_11n_disable.conf or awlagn.conf.

/etc/modprobe.d/blacklist

If you don't want a driver to load at boot you add it to this list. Usually this is used if you have a driver conflict and/or you want to make sure a specific driver is used. Note: this method will not work unless the diver is a LKM (loadable kernel module) If driver/module was compiled into the base kernel, it will still load if blacklisted.

CategoryNetworking CategoryWireless