According to Wikipedia, a router is a networking device that forwards data packets between computer networks. If we tear-down a wireless router, we will probably find an application specific processor that handles data packets and an RF segment that handles wireless connectivity.

You know what else has a processor and an RF segment.

THAT'S RIGHT a raspberry pi model 3. So in this miniProject, we will convert a raspberry pi to act as a router.

Step 1: Video

Take a look at video for quick comprehensive guide in 3 mins.

Step 2: Boot-up Raspberry Pi.

First step is to get your raspberry pi up and running. Official getting started guide on Raspberry pi website is best resource for this.

Here is the link.

Go to next step once you have your raspberry pi up and running.

Step 3: Upgrading Raspberry Pi

First we will update package list available from repositories using

sudo apt-get update

Once done, we can install these latest packages using

sudo apt-get upgrade

This might take a while depending on your internet connection speed.

Step 4: Installing Hostadp and Bridge-utils

Once raspberry pi is upgraded.

we need to install a user space background process called hostapd, used for wireless access points and authentication servers. We will also need a package called bridge-utils to manage bridge devices.

sudo apt-get install hostapd bridge-utils

We need to turn off some of the new services that we just installed do it using

sudo systemctl stop hostapd

Debug- Some times raspbian will display message saying hostapd and bridge-utils not found for install command. Do not worry. Run 'sudo apt-get update' once more and it should get resolved.

Step 5: Disable DHCP Config for Wlan0 and Eth0

Now, we set dhcp background process not to automatically configure wlan0 and eth0 interfaces. We do this by putting following two lines

denyinterfaces wlan0
denyinterfaces eth0

at the end of /etc/dhcpcd.conf file, open it using.

sudo nano /etc/dhcpcd.conf

Step 6: Creating Bridge Br0

Next, we create a bridge br0 using brctl command which is an Ethernet bridge administrator

sudo brctl addbr br0

and using

sudo brctl addif br0 eth0

command we add eth0 as one of the ports for bridge br0.

Step 7: Edit /etc/network/interfaces

Now open up a file called interfaces in /etc/network directory

sudo nano /etc/network/interfaces

and add these five lines.

allow-hotplug wlan0
iface wlan0 inet manual

auto br0
iface br0 inet dhcp
bridge_ports eth0 wlan0

First line starts wlan0 interface on a hotplug event. Second line creates a network interface without an IP address which is normally done for bridge elements. Third line starts br0 interface on boot up. Forth line helps in automatic assignment of IP address to br0 interface using DHCP server and finally fifth line connects eth0 interface with wlan0. Save this file and close it.

Step 8: Edit /etc/hostapd/hostapd.conf

Next, we will configure our wireless access point, we can do this using a file called hostapd.conf in /etc/hostapd folder. Open it up

sudo nano /etc/hostapd/hostapd.conf

and paste these lines.

interface=wlan0
bridge=br0
ssid=miniProjects
hw_mode=g
channel=7
wmm_enabled=0
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=subscribe
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP

Value assigned to ssid is the name that access point will use to broadcast its existence. Last five lines are focused on authentication and security of access point. Value of wpa_passsphrase is used as login password which is subscribe in our case. This is a link to document, where you can find definition of each variable that we have used here.