It should be the name of the machine. Do not put your domain suffix on it. This should be what you call the machine. It usually contains one line. This is where we will define the nameservers that your machine will use, as well as the domain suffix search order you want to use.
Most people like to add another nameserver and add to the search order.
Your Linux system should now be configure to work with ResNet. Reboot your computer for the changes to take effect.