Goal:
The goal of this guide is to turn a Raspberry Pi into a wireless home/mobile router.
Equipment:
- Raspberry Pi with raspbian
- Wireless USB device. The guide uses a Edimax Nano USB Wifi (EW-7811Un) adapter
- Ethernet cat5 cable to connect to the Internet
Lets get started.
Install the following packages.
sudo apt-get install hostapd dnsmasq iptables
Open up “/etc/network/interfaces” and add the following lines. If there is a line for wlan0 you can comment it out with a “#”.
iface wlan0 inet static address 192.168.42.17 netmask 255.255.255.0
Configure Hostapd
Edit the following file “/etc/default/hostapd” so it looks like this.
DAEMON_CONF="/etc/hostapd/hostapd.conf"
Now edit the hostapd config file “/etc/hostapd/hostapd.conf” and configure the wireless access point.
interface=wlan0
driver=rtl871xdrv
bridge=br0
ssid=MC
channel=1
wmm_enabled=0
wpa=1
wpa_passphrase=min3cr@ft
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP
auth_algs=1
macaddr_acl=0
Configure the DHCP Server
For the DHCP server we just need to add the following lines to “/etc/dnsmasq.conf”
interface=wlan0 dhcp-range=192.168.42.20,192.168.42.152,255.255.255.0,12h dhcp-option=3,192.168.42.17
Configure Iptables
Now we need to set it up so the pi can forward traffic from wlan0 to eth0.
Edit “/etc/sysctl.conf” and uncomment the following line
net.ipv4.ip_forward=1
then execute
sysctl -p
Next create an iptables “config” file.
sudo touch /etc/network/if-up.d/router.sh sudo chmod +x /etc/network/if-up.d/router.sh sudo su -c "echo '/etc/network/if-up.d/router.sh' >> /etc/rc.local"
Add the following line to the file.
sudo iptables --table nat --append POSTROUTING --out-interface eth0 -j MASQUERADE sudo iptables --append FORWARD --in-interface wlan0 -j ACCEPT
If you are using the same wireless adapter that is used in this guide then you will need to execute the following commands to replace the hostapd binary. You can find more info here.
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
That should do it. Plug in the Ethernet cable and reboot your pi and you should be good to go.