Raspberry pi as wireless router

I will be showing how to turn the Raspberry Pi into a wireless access point to which other devices can connect basically, we are turning the raspberry pi into a wireless “router”. I will also show us how to set up the wireless access point created to provide (share) internet access to(with) connected devices.

Also, it is possible to Integrate with LTE over USB and ability to work raspberry pi with LTE as an independent mini Wireless router.

A routed wireless access point can be created using the inbuilt wireless features of the Raspberry Pi 3 by using a suitable USB wireless dongle that supports access point mode.

Here's how I have done

Go to this link here to set up your raspberry pi. Once setup is done let’s begin creating Wi-Fi Hotspot with Raspberry Pi.

STEP-1:

Raspberry Pi OS Update

As usual, we update the raspberry pi to ensure we have the latest version of everything

sudo apt-get update
sudo apt-get upgrade

STEP-2:

Install Access Point Management Software Packages

To work as an access point, the Raspberry Pi needs to have some of the software packages to act as an access point.

Below commands will install the software that makes it possible to set up the pi as a wireless access point and also the software that helps assign a network address to devices that connect to the AP.

sudo apt install hostapd
sudo apt install dnsmasq

Finally, install netfilter-persistent and its plugin iptables-persistent. This utility helps by saving firewall rules and restoring them when the Raspberry Pi boots.

sudo DEBIAN_FRONTEND=noninteractive apt install -y netfilter-persistent iptables-persistent

Before going to the next step reboot raspberry pi.

sudo reboot

STEP-3:

Set up the Network Router

The Raspberry Pi will run and manage a standalone wireless network. It will also route between the wireless and Ethernet networks, providing internet access to wireless clients. Setting up the Raspberry Pi to act as a server requires us to assign a static IP address to the wireless port. This can be done by editing the dhcpcd config file. To edit dhcpcd.conf file gives the below command.

sudo nano /etc/dhcpcd.conf

Go to the end of the dhcpcd.conf file and add the following lines

interface wlan0
    static ip_address=192.168.4.1/24
    nohook wpa_supplicant

STEP-4:

Enable Routing and IP Masquerading

To allow traffic to flow from one network to the other in the Raspberry Pi, create a file using the following command, with the contents below:

sudo nano /etc/sysctl.d/routed-ap.conf

File contents:

# Enable IPv4 routing
net.ipv4.ip_forward=1

Enabling routing will allow hosts from network 192.168.4.0/24 to reach the LAN and the main router towards the internet.

This process is configured by adding a single firewall rule in the Raspberry Pi

sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

Now save the current firewall rules for IPv4 (including the rule above) and IPv6 to be loaded at boot by the netfilter-persistent service using the below command

sudo netfilter-persistent save

STEP-5:

Configure the DHCP and DNS services for the wireless network

The DHCP and DNS services are provided by dnsmasq. The default configuration file serves as a template for all possible configuration options.

Rename the default configuration file and edit a new one

sudo mv /etc/dnsmasq.conf /etc/dnsmasq.conf.orig
sudo nano /etc/dnsmasq.conf

Add the following to the file and save it,

interface=wlan0
dhcp-range=192.168.4.2,192.168.4.20,255.255.255.0,24h
domain=wlan
address=/gw.wlan/192.168.4.1

To ensure WiFi radio is not blocked on your Raspberry Pi, execute the following command:

sudo rfkill unblock wlan

This setting will be automatically restored at boot time. We will define an appropriate country code in the access point software configuration.

STEP-6:

Configure the AP Software

Create the hostapd configuration file, located at /etc/hostapd/hostapd.conf, to add the various parameters for your new wireless network.

country_code=IN
interface=wlan0
ssid=SSID
hw_mode=g
channel=7
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=PWD
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP

NOTE :country_code it configures the computer to use the correct wireless frequencies. See Wikipedia for a list of two-letter ISO 3166-1 country codes.

*SSID : Your SSID (my Case DEV_AP01)

*PWD: Your Password (my Case Pi@12345)

To effect the changes made to the Raspberry Pi, reboot the system.

sudo systemctl reboot

Once it comes back up, you should now be able to access the internet by connecting to the Wireless access point created by the Raspberry Pi.

Note: It might take a while for the Wireless access point to become visible after reboot as the Pi needs to boot up before the network activities start

Finally, it's working with L501(LTE module). Internet accessed from L501 and provided to the connected devices.

Thanks for taking the time to read. Feedback and comments are always welcome.