[CentOS] Linux hosts file /etc/hosts

> Is it good measure to add it to the hosts file anyway or is this a waste
> of time? I guess my understanding of the host file is clouded.
>

Yes, waste of time.  It's all in how you've configured postfix to handle
it.  The default is to the FQDN of the server, but I'd suggest you change
accordingly (ie: myhostname).