RaspberryPi/Access Point

Configure RPi As Wireless Access Point

these instructions will walk you through setting up raspberry pi as wireless access point.

start by connecting to your pi via ssh. Install some software needed to turn the RPi into a router:

$ apt-get install -y hostapd udhcpd iw

Now pick out a wireless USB adapter that can act as an access point.

$ iw list | grep "* AP"

(If no results, try a different wireless card.)

View the name server (DNS) address stored in /etc/resolve.conf

Now let's configure the DHCP server, which is responsible for handing out leases.

Edit /etc/udhcpd.conf, use sample file below:

# Sample udhcpd configuration file (/etc/udhcpd.conf)

# The start and end of the IP lease block
start           192.168.0.20    #default: 192.168.0.20
end             192.168.0.254   #default: 192.168.0.254

# The interface that udhcpd will use
interface       eth0            #default: eth0

# Settings
opt     dns     192.168.2.1
option  subnet  255.255.255.0
opt     router  192.168.0.1
option  domain  local
option  lease   864000

This assumes that the resolve.conf file contained 192.168.2.1.

Now edit one more file: /etc/default/udhcpd

# Comment the following line to enable
DHCPD_ENABLED="no"

# Options to pass to busybox' udhcpd.
#
# -S    Log to syslog
# -f    run in foreground

DHCPD_OPTS="-S"

Now you're ready to enable DHCP server, simply by commenting out DHCPD_ENABLED="no"

Change it to #DHCPD_ENABLED="no" and you'll be ready to go.

Configure the hostapd server by editing the file /etc/hostapd/hostapd.conf and adding the following contents:

interface=wlan0
ssid=CIA_Surveillance_Van
wpa_passphrase=ITSASECRET
driver=nl80211
hw_mode=g
channel=6
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP

Now enable the hostapd service by creating a default file in

/etc/default/hostapd</code>

<pre>
# Uncomment and set DAEMON_CONF to the absolute path of a hostapd configuration
# file and hostapd will be started during system boot. An example configuration
# file can be found at /usr/share/doc/hostapd/examples/hostapd.conf.gz
#
#DAEMON_CONF=""

# Additional daemon options to be appended to hostapd command:-
#       -d   show more debug messages (-dd for even more)
#       -K   include key data in debug messages
#       -t   include timestamps in some debug messages
#
# Note that -B (daemon mode) and -P (pidfile) options are automatically
# configured by the init.d script and must not be added to DAEMON_OPTS.
#
#DAEMON_OPTS=""
~                                                                                                                       
"/etc/default/hostapd" 20 lines, 770 characters
Replace the line beginning with #DAEMON_CONF with the line DAEMON_CONF="/etc/hostapd/hostapd.conf".
DAEMON_CONF="/etc/hostapd/hostapd.conf"
Save the file and exit the editor (:wq).
Configure IP forwarding. Use the vi editor to enable IP forwarding by editing the kernel parameters file, /etc/sysctl.conf.
pi@raspberrypi ~ $ sudo vi /etc/sysctl.conf
The vi editor displays the contents of the configuration file.
#
# /etc/sysctl.conf - Configuration file for setting system variables
# See /etc/sysctl.d/ for additonal system variables
# See sysctl.conf (5) for information.
#