Configure Network Address Translation
Setting up NAT will allow multiple clients to connect to the WiFi and have all the data ‘tunneled’ through the single Ethernet IP. (But you should do it even if only one client is going to connect)
Run
sudo vi /etc/sysctl.conf
uncomment this line (or scroll to the bottom and add if it is not there!)
net.ipv4.ip_forward=1
Save the file. This will start IP forwarding on boot up.
To reload the file without rebooting .. sudo sysctl -p
Run the following commands to create the network translation between the ethernet port eth0 and the wifi port wlan0
sudo iptables –t nat –A POSTROUTING –o eth0 –j MASQUERADE
sudo iptables –A FORWARD –i eth0 –o wlan0 –m state —state RELATED,ESTABLISHED –j ACCEPT
sudo iptables –A FORWARD –i wlan0 –o eth0 –j ACCEPT
You can check to see whats in the tables with
sudo iptables -t nat -S
sudo iptables -S
To make this happen on reboot (so you don’t have to type it every time) run
sudo sh -c “iptables-save > /etc/iptables.ipv4.nat”
run
and add
up iptables-restore < /etc/iptables.ipv4.nat
to the very end
For USB tether sharing .. add
sudo iptables -t nat -A POSTROUTING -o usb0 -j MASQUERADE
sudo iptables -t nat -A POSTROUTING -o usb0 -j MASQUERADE
sudo iptables -A FORWARD -i wlan0 -o usb0 -j ACCEPT
rather !
iptables -t nat -A POSTROUTING -o usb0 -j MASQUERADE
iptables -A FORWARD -m conntrack –ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -i eth0 -o usb0 -j ACCEPT
after following:
https://www.raspberryconnect.com/projects/65-raspberrypi-hotspot-accesspoints/157-raspberry-pi-auto-wifi-hotspot-switch-internet