Configuring Wireless on NTCOMMLinux

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Configuring Wireless on NTCOMMLinux

• A Hands-On Guide
• Justin Grote
• NTCOMM425 Special Topics Wireless
• 02 March 2005

2
Tasks to Setup Wireless

• Physically Install/Insert Wireless Card
• Install Kernel Module/Driver
• Place firmware where it can be located
• Install Wireless Tools
• Initially Configure Wireless Card
• Configure OS so that card is configured on startup

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Tasks to Setup Wireless(for today)

• Physically Install/Insert Wireless Card
• Install Kernel Module/Driver
• Place firmware where it can be located
• Install Wireless Tools
• Initially Configure Wireless Card
• Configure OS so that card is configured on startup

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CLI vs. GUI Configuration

• CLI
• Usually Universal across Linux Distributions
• Faster
• More options and tweaks usually available
• Much more likely to work on a broken system
• - Not very intuitive

• GUI
• Easier on the eyes, Easier on the mind
• Constraints provide guidance
• Point-and-click
• - Less Options usually available
• - Varies across distributions

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Various GUI Interfaces
KDE's KWifiManager
Suse's YAST (Yet another Setup Tool)
Fedora's System-config-network
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Wireless Card Info Commands

• Try these now! You can!
• iwconfig
• Provides general information about the wireless
  card
• Also used to configure the card, but can only be
  done as root on NTCOMMLinux
• iwevent
• Watches the card for changes or events such as
  reassociation, configuration changes, etc.
• iwlist
• Provides more detailed information about the
  wireless card. NOTE Some information is not
  refreshed automatically unless you are root.
• iwpriv
• Get down and dirty into the card (including
  Txpower, etc.)

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More Detailed Wireless Info

• Iwlist scan
• Finds all wireless networks within range. This is
  only actively done by root, everyone else gets
  leftovers
• Iwlist accesspoints
• If in an ESS, this will list all neighboring AP's
  in the same ESS
• Iwlist retry
• Show the retry timers for the wireless card.

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Basic Wireless Configuration

• iwconfig wlan0 essid NTCommLinux
• Sets the ESSID to NTCommLinux
• iwconfig wlan0 channel 3
• Sets the channel to 3. Can also use frequencies
  here (i.e. Iwconfig wlan0 channel 2.425Ghz)
• iwconfig wlan0 mode Master
• Turns NTCOMMLinux into an AP. Other valid options
  include Ad-Hoc, Managed (manual client), Monitor
  (stealthily listen), Repeater (for bridging), and
  Auto (associate with the network with the
  strongest signal strength)
• Now the ifconfig parameters

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Usual Interface Configuration

• Ifconfig wlan0 172.16.160.1 netmask 255.255.255.0
• Sets up the card with an IP address and a /24
  mask. The program will infer the other
  information such as broadcast, subnet, etc.
• Adding routes is not necessary in this case,
  since it is just a single network that will be
  added automatically. Usually you will add a
  default gateway however with
• route add default gw x.x.x.x

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Manual Config Disclaimer

• THE CHANGES THAT WERE JUST MADE ARE NOT
  PERSISTENT, THEY ARE ONLY STORED IN RAM.
• RESTART SERVER CHANGES ARE GONE

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Config on Fedora

• Start system-config-network as root
• Go to the device (or create new if not set up
  yet) and configure it
• Once configured, this information is stored in
  /etc/sysconfig/network-scripts, and is restored
  every time the server is restarted.

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Wireless Apps

• Ethereal ( www.ethereal.com )
• Not really a wireless ap per-se, but works just
  fine to capture wireless traffic
• Airsnort ( airsnort.shmoo.com )
• The program that popularized WEP keybreaking.
  Give it a day and a wireless network and it will
  give you a WEP key
• Kismet ( www.kismetwireless.net )
• The inspiration for NetStumbler. A command-line
  program that watches the airwaves for access
  points and clients.
• Wellenreiter ( www.wellenreiter.net )
• A program for finding and cataloging wireless
  networks. Very detailed and good drill-down,
  useful if you can't afford airmagnet.
• Other fun Tools
• WaveStumbler, Hotspotter, Airsnarf, and
  morehttp//corky.net/2600/wireless-networks/wi-fi
  -software-tools.shtml

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Key Points

• Wireless on Linux is fully supported, and even
  included by default in most modern distributions
• There are two ways of setting it up, either with
  a command line or with a graphical tool. Each has
  its pros and cons.
• Wireless in Linux is very powerful and highly
  flexible, and can be customized to any need, be
  it AP, network monitor, client, or even 802.11i
  authentication server.