Raspbian : wifi hotspot

Prerequisites

The first thing you need to do is make sure you have an existing wired connection to your rPi. After that, you need to install the following packages.

sudo apt-get install bridge-utils hostapd

The whole crux of the issue is that it is the apt hosted copy of hostapd that is not compatible with the RTL8188CUS chipset. But, thanks to the Edimax team, I’ve got a replacement hostapd binary to resolve this issue. This tutorial will not work without it.

To download and replace the installed binary version of hostapd we just installed, issue the following commands:

wget http://www.daveconroy.com/wp3/wp-content/uploads/2013/07/hostapd.zip
unzip hostapd.zip 
sudo mv /usr/sbin/hostapd /usr/sbin/hostapd.bak
sudo mv hostapd /usr/sbin/hostapd.edimax 
sudo ln -sf /usr/sbin/hostapd.edimax /usr/sbin/hostapd 
sudo chown root.root /usr/sbin/hostapd 
sudo chmod 755 /usr/sbin/hostapd

• Note, some people don’t like the idea of installing from untrusted 3rd parties, so if If would rather compile your own binary, you can download the realtek driver here . You will have to navigate to the ~/RTL8188C_8192C_USB_linux_v3.4.4_4749.20121105/wpa_supplicant_hostapd/wpa_supplicant_hostapd-0.8/hostapd and run a make, make install, then hostapd like i did above.

Bridge the Network Connections

Now that we have the proper hostapd installed, we need to create a bridge between our ethernet connection and our Edimax Wireless card. To do this, we need to edit our network interfaces:

sudo nano /etc/network/interfaces

To avoid any conflicts, you need to delete or comment out(#) any lines conatining wlan0 and then add the following text to bridge the connections, assuming your ethernet and wireless adapters are named eth0 and wlan0( use ifconfig -a to check)

   auto br0
   iface br0 inet dhcp
   bridge_ports eth0 wlan0 

The resulting file should look like this:

   #loopback adapter
   auto lo
   iface lo inet loopback

   #wired adapter
   iface eth0 inet dhcp

   #bridge
   auto br0
   iface br0 inet dhcp
   bridge_ports eth0 wlan0

Configuring Hostapd

Now that our interfaces are setup, we need to configure hostapd. To do so, create the following file

sudo nano /etc/hostapd/hostapd.conf

with the following contents:

   interface=wlan0
   driver=rtl871xdrv
   bridge=br0
   ssid=DaveConroyPi
   channel=1
   wmm_enabled=0
   wpa=1
   wpa_passphrase=ConroyPi
   wpa_key_mgmt=WPA-PSK
   wpa_pairwise=TKIP
   rsn_pairwise=CCMP
   auth_algs=1
   macaddr_acl=0 

Wrapping Up

We should be finished now, and afer a reboot

sudo reboot

you can test your configuration using the following command

sudo hostapd -dd /etc/hostapd/hostapd.conf

If it runs as expected, you can add it to startup by editing

sudo nano /etc/default/hostapd

and uncommenting and updating the following line

   DAEMON_CONF="/etc/hostapd/hostapd.conf"

Taken from: http://www.daveconroy.com