Access Point

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Revision as of 19:00, 30 June 2010 by Phenigma (Talk | contribs) (Using nl80211 drivers (from backports))

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Usage Information


This tutorial describes how to add Access Point functionality to your LinuxMCE Core/Hybrid. The Core/Hybrid will then act as a WiFi access point permitting wireless devices to connect to the core, the internal network and the internet. The drivers you choose will depend on your specific hardware. Setting up an Access Point on your core allows you to use wireless orbiters such as the WebDT 366 or Nokia N800/N900 without installing a seperate wireless access point on your network.

Using nl80211 drivers (from backports)

Hardware setup

  • Zotac IONITX-A-U Atom N330 1.6 Ghz with GB Lan and WLan
    • Atheros Communications Inc. AR928X Wireless Network Adapter (PCI-Express) (rev 01)
    • USB 10/100 Ethernet Adaptor
  • LinuxMCE 0810 BETA - Snapshot DVD - 28-Jun-2010


  • -> eth0 is the onboard 1GB ethernet, connects to internal network
  • -> eth1 is a USB 10/100, connects to a cable modem for internet
  • -> wlan0 is the onboard mini PCI-Express wifi card

Required packages

Add the intrepid-backports repository

Adding the intrepid-backports repo gives us access to newer wireless drivers, including the newer ath9k module required for the Zotac's Atheros (AR928X) wifi card.

$ echo 'deb intrepid-backports main universe' | sudo tee -a /etc/apt/sources.list
$ sudo apt-get update

Install required packages

Install compat-wireless drivers including the mac80211/cfg80211 modules and the network bridge utilities.

$ sudo apt-get install linux-backports-modules-intrepid bridge-utils

Dowload, build and install hostapd

The hostapd package that ships with intrepid (0.5.10) is outdated, newer functionality is required. Grab the most recent version that works with the compat-wireless drivers that we installed.

Install build dependencies for hostapd

$ sudo apt-get install libnl-dev libssl-dev

Get hostapd 0.6.9

$ wget
$ tar xvf hostapd-0.6.9.tar.gz
$ cd hostapd-0.6.9/hostapd
$ cp defconfig ./.config

Edit the .config file to enable the proper drivers:

  • Enable nl80211 driver
  • Enable IEEE 802.11n (High Throughput) support

Build and Install hostapd

$ make
$ sudo make install

Copy the config file to /etc/hostapd

$ sudo mkdir -p /etc/hostapd
$ sudo cp hostapd.conf /etc/hostapd

Config Files


Make a backup of your original interfaces file:

$ sudo mv /etc/network/interfaces /etc/network/interfaces.bak

The interfaces file shown here is based on the setup described in the overview above.

auto lo eth1 br0 eth0
# Loopback Interface
iface lo inet loopback
# Internet Interface
iface eth1 inet dhcp
# LAN Interface
iface eth0 inet manual
	up /sbin/ifconfig eth0 up
	down /sbin/ifconfig eth0 down
# Wireless Interface
iface wlan0 inet manual
# Wireless/LAN Bridge
iface br0 inet static
	pre-up /usr/sbin/brctl addbr br0
	pre-up /usr/sbin/brctl addif br0 eth0
	pre-up /usr/local/bin/hostapd -B /etc/hostapd/hostapd.conf
	pre-up /usr/sbin/brctl addif br0 wlan0
	up /sbin/ifconfig br0 up
	post-down /usr/sbin/brctl delif br0 eth0
	post-down /usr/sbin/brctl delif br0 wlan0
	post-down /usr/sbin/brctl delbr br0


Edit /etc/hostapd/hostapd.conf and verify/change the following:



Configure the dhcp server to respond to request from devices on the bridge instead of the wired connection alone.

$ echo 'INTERFACES="br0"' | sudo tee /etc/default/dhcp3-server


All security/encryption related settings are in /etc/hostapd/hostapd.conf. Edit this file as needed.

Restart Networking

Restart the networking engine, or reboot.

$ sudo service networking restart

Using madwifi drivers


Hardware setup

  • Dell Optiplex Gx620
  • WiFi card with Atheros chipset (using madwifi drivers)
  • Linux MCE 810 alpha2

If you install LMCE from scratch make sure that your wifi card is NOT inserted prior to installation so that LMCE doesn't use it as the internal network interface. After LCME installation has finished, insert the wifi card.


the idea is to combine or bridge eth1 and ath0 to a new virtual interface called br0.

  • -> eth0 connects to my ADSL modem (
  • -> eth1 connects to my internal LAN switch (
  • -> ath0 connects the wireless part of my internal network (

Needed packages

  • hostapd
  • bridge

Config files


We'll make a copy of /etc/network/interfaces in case something goes wrong before we edit it.

mv /etc/network/interfaces /etc/network/interfaces.bck
joe /etc/network/interfaces
auto lo eth0 eth1 br0

automatically initialise eth0 (external interface) eth1 (internal LAN) and br0 (our bridge interface). Keep ath0 out of this for now, we'll initialise it separately.

iface lo inet loopback
# Internet Interface
iface eth0 inet static

Fill in your own settings here, in my case is the ADSL modem. Alternatively you can use dhcp to get the adress details from your ADSL modem.

# LAN interface
iface eth1 inet manual
  up /sbin/ifconfig eth0 up
  down /sbin/ifconfig eth0 down

The internal interface, note that it doesn't get an adress assigned.

# Wireless interface
auto ath0
iface ath0 inet manual
  up /sbin/ifconfig ath0 up

The wireless interface, again no adress details here.

iface br0 inet static
   pre-up /usr/sbin/brctl addbr br0
   pre-up /usr/sbin/brctl addif br0 eth1

The fun part. Finally we assign the adress for the internal LAN to the bridge interace br0 (I'm sticking here with the standard LMCE network 80.0). The pre-up will create a bridge and add the eth1 interface to it.

   pre-up /sbin/wlanconfig ath0 destroy
   pre-up /sbin/wlanconfig ath0 create wlandev wifi0 wlanmode ap
   pre-up /sbin/iwconfig ath0 channel 3

This part is necessary as the atheros interface has some issues to switch ino access point mode (master mode)

   pre-up /usr/sbin/brctl addif br0 ath0

After firing up the wireless interface we add it to the bridge as well.

   post-down /usr/sbin/brctl delif br0 eth1
   post-down /usr/sbin/brctl delif br0 ath0
   post-down /usr/sbin/brctl delbr br0

Just some lines to define how to cleanly shut down the bridge: remove both interfaces and then remove the bridge interace itself

We need to set the bridge (which contains eth1 and ath0) as the new interface for the dhcpd server. Edit /etc/default/dhcp.conf as followed:



wireless configuration

We'll use hostapd to manage the wireless part as it provides WPA encryption. I suggest that you first try to setup your network without encryption, make sure it works and then enable encryption.

Enable WPA encryption

  • edit the /etc/hostapd

Set static IP adresses

It is possible to set static ip adresses manually instead of using LMCE.