Ubuntu: Share internet connections with other computers

You can configure a Ubuntu system as a gateway in order to share it's internet connection (maybe via WLAN or tethering) with other computers on the network.

On the gateway

• Enable ip traffic forwarding:

  • Open /etc/sysctl.conf

  • Uncomment the line

    Copynet.ipv4.ip_forward=1
    

  • Reload using sudo sysctl -p /etc/sysctl.conf

• Reconfigure ip_tables to allow NAT:
  • Download the attached file
  • Replace online_device with the name of the network device that provides the internet connection
  • Replace lan_device with the name of the network device that connects to the LAN
  • Run the script with sudo

On the client PC

Add the gateway PC as the default gateway using

Copysudo ip route del default
sudo ip route add default via <ip of gateway pc>

Add another DNS server to /etc/resolv.conf, for example

Copynameserver 8.8.8.8