Question

How to enable IP forwarding on a Debian machine?

Answer 1

Open Terminal and log into root using sudo su followed by your password then type: pico /etc/sysctl.conf. If you don't have pico, you might want to install it using: apt-get install pico. In the .conf file, identify line that has the following: net.ipv4.ip_forward and change it to 1 instead of 0. Press Ctrl+O followed by CTRL+X then from the same Terminal window, use: sysctl -p to restart the interfaces and you're done.

Answer 2

Editing the sysctl.conf file should give you the following screen:

As you can see, I have edited the file with the IP forwarding; and after I've removed the # I have pressed Ctrl+O to save the file.

Next you want to restart the interface with the sysctl -p command:

You now have IP forwarding enabled.