Configuring Raspberry PI as your Ethernet router

Configure your WiFi

• sudo raspi-config

• select "2 Network Options      Configure network settings"

• then select "N2 Wi-fi                   Enter SSID and passphrase"

• enter your access point and password

• you are done

Install a lightweight network (DHCP, DNS) infrastructure 

• sudo apt-get install dnsmasq

Stop the service until we configure if fully 

• sudo systemctl stop dnsmasq

Configure Static WiFi for dhcp client

• sudo vi /etc/dhcpcd.conf
  

Type the following statements

• interface eth0
• static ip_address=192.168.10.1/24
• static domain_name_servers=192.168.0.1 8.8.8.8

Restart the dhcp client daemon

• sudo service dhcpcd restart

Let us configure the dhcp server

• sudo mv /etc/dnsmasq.conf /etc/dnsmasq.conf.orig 
• sudo vi /etc/dnsmasq.conf

type the following 

• interface=eth0
• dhcp-range=192.168.10.2,192.168.10.20,255.255.255.0,24h

Add a Routing and Masqueraed 

• Edit /etc/sysctl.conf and uncomment this line:
• net.ipv4.ip_forward=1
   
• Add a masquerade for outbound traffic on wlan0:
• sudo iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE 

• Save the iptables rule.
• sudo sh -c "iptables-save > /etc/iptables.ipv4.nat"

• Edit /etc/rc.local and add this just above "exit 0" to install these rules on boot.
• iptables-restore < /etc/iptables.ipv4.nat

Reboot

Your raspberrypi is now ready as a WiFi ==> Ethernet router