It is said in Linode's doc that:
Next, edit your /etc/hosts file to resemble the following example, replacing "plato" with your chosen hostname, "example.com" with your system's domain name, and "22.214.171.124" with your system's IP address. As with the hostname, the domain name part of your FQDN does not necesarily need to have any relationship to websites or other services hosted on the server (although it may if you wish). As an example, you might host "www.something.com" on your server, but the system's FQDN might be "mars.somethingelse.com."
127.0.0.1 localhost.localdomain localhost
126.96.36.199 plato.example.com plato
Since it says "the domain name part of your FQDN does not necesarily need to have any relationship to websites or other services hosted on the server", does that mean I can use "plato.somenonexistdomain.com" on the second line?
Does that mean, only the first IP part and the last hostname part is need to be true?