Raspberry Pi WiFi Server

Plug the WiFi module into the Pi and start it up.

After initial setup, run the following to see if the WiFi module shows as wlan0.

ifconfig -a

Install software

Next up we install the software onto the Pi that will act as the ‘hostap’ (host access point) You need internet access for this step so make sure that Ethernet connection is up!

sudo apt-get install hostapd isc-dhcp-server

Set up DHCP server

Next we will edit /etc/dhcp/dhcpd.conf, a file that sets up our DHCP server – this allows wifi connections to automatically get IP addresses, DNS, etc.

Run this command to edit the file

sudo nano /etc/dhcp/dhcpd.conf

Find the lines that say

option domain-name "example.org";
option domain-name-servers ns1.example.org, ns2.example.org;

and change them to add a # in the beginning so they say

#option domain-name "example.org";
#option domain-name-servers ns1.example.org, ns2.example.org;

Find the lines that say

# If this DHCP server is the official DHCP server for the local
# network, the authoritative directive should be uncommented.
#authoritative;

and remove the # so it says

# If this DHCP server is the official DHCP server for the local
# network, the authoritative directive should be uncommented.
authoritative;

Then scroll down to the bottom and add the following lines
Copy Code

subnet 192.168.42.0 netmask 255.255.255.0 {
range 192.168.42.10 192.168.42.50;
option broadcast-address 192.168.42.255;
option routers 192.168.42.1;
default-lease-time 600;
max-lease-time 7200;
option domain-name "local";
option domain-name-servers 8.8.8.8, 8.8.4.4;
}

Save the file by typing in Control-X then Y then return

Run

sudo nano /etc/default/isc-dhcp-server

and scroll down to INTERFACES=”” and update it to say INTERFACES=”wlan0″

Set up wlan0 for static IP

If you happen to have wlan0 active because you set it up, run sudo ifdown wlan0
There’s no harm in running it if you’re not sure

Next we will set up the wlan0 connection to be static and incoming. To edit the file run:

</pre>
sudo nano /etc/network/interfaces
<pre>

Find the line auto wlan0 and add a # in front of the line, and in front of every line afterwards. If you don’t have that line, just make sure it looks like the screenshot below in the end! Basically just remove any old wlan0 configuration settings, we’ll be changing them up

Depending on your existing setup/distribution there might be more or less text and it may vary a little bit

Change Code to:

Auto lo
iface lo inet loopback
iface eht0 inet dhcp

allow-hotplug wlan0

iface wlan0 inet static
  address 192.168.42.1
  netmask 255.255.255.0

#iface wlan0 inet manual
#wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
#iface default inet dhcp

After allow hotplug wlan0 – see below for an example of what it should look like. (ignore our hyphen in allow-hotplug tho, its a typo!) Any other lines afterwards should have a # in front to disable them

Save the file (Control-X Y )

Assign a static IP address to the wifi adapter by running

sudo ifconfig wlan0 192.168.42.1

Configure Access Point

Now we can configure the access point details. We will set up a password-protected network so only people with the password can connect.

Create a new file by running

sudo nano /etc/hostapd/hostapd.conf

Paste the following in, you can change the text after ssid= to another name, that will be the network broadcast name. The password can be changed with the text after wpa_passphrase=

interface=wlan0
driver=rtl871xdrv
ssid=Pi_AP
hw_mode=g
channel=6
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=Raspberry
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP

If you are not using the Adafruit wifi adapters, you may have to change the driver=rtl871xdrv to say driver=nl80211 or something, we don’t have tutorial support for that tho, YMMV!

Save as usual. Make sure each line has no extra spaces or tabs at the end or beginning – this file is pretty picky!

Now we will tell the Pi where to find this configuration file. Run

sudo nano /etc/default/hostapd

Find the line #DAEMON_CONF=”” and edit it so it says DAEMON_CONF=”/etc/hostapd/hostapd.conf”
Don’t forget to remove the # in front to activate it!

Then save the file

Update hostapd

Before we can run the access point software, we have to update it to a version that supports the WiFi adapter.

First get the new version by typing in

wget http://www.adafruit.com/downloads/adafruit_hostapd.zip

to download the new version (check the next section for how to compile your own updated hostapd) then

unzip adafruit_hostapd.zip

to uncompress it. Move the old version out of the way with

sudo mv /usr/sbin/hostapd /usr/sbin/hostapd.ORIG

And move the new version back with

sudo mv hostapd /usr/sbin

set it up so its valid to run with

sudo chmod 755 /usr/sbin/hostapd

First test!

Finally we can test the access point host! Run

sudo /usr/sbin/hostapd /etc/hostapd/hostapd.conf

To manually run hostapd with our configuration file. You should see it set up and use wlan0 then you can check with another wifi computer that you see your SSID show up. If so, you have successfully set up the access point.

You can try connecting and disconnecting from the Pi_AP, debug text will display on the Pi console but you won’t be able to connect through to the Ethernet connection yet.

Cancel the test by typing Control-C in the Pi console to get back to the Pi command line

Setting Startup Services

OK now that we know it works, time to set it up as a ‘daemon’ – a program that will start when the Pi boots.
Run the following commands

sudo service hostapd start
sudo service isc-dhcp-server start

you can always check the status of the host AP server and the DHCP server with

sudo service hostapd status
sudo service isc-dhcp-server status

To start the daemon services. Verify that they both start successfully (no ‘failure’ or ‘errors’)
Then to make it so it runs every time on boot

sudo update-rc.d hostapd enable
sudo update-rc.d isc-dhcp-server enable

Extra: Removing WPA-Supplicant

Depending on your distro, you may need to remove WPASupplicant. Do so by running this command:

sudo mv /usr/share/dbus-1/system-services/fi.epitest.hostap.WPASupplicant.service ~/

and then rebooting (sudo reboot)

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