I attempting to install Scalix (email server) to a brand new linux box and coming up with the following errors in my log:

Network check failed:

Hosts file is not configured with fully qualified domain name (FQDN)
Could not find a host name in DNS that matches an IP address
Could not resolve host name 'localhost.waldenwebsites.net' in DNS
127.0.0.1 line contains server hostname (localhost) in /etc/hosts, please remove it

Network check warning:

Network is configured to DHCP

I am very new to Linux and networking the same. Does anyone know what these messages are actually telling me and how to go about fixing them? I'm happy to do my research, but I'm a bit confused right now as where to start.

Thanks!

check whether DNS server is working or not
configure host file with your IP and FQDN
configure DNS for your dmain name

My question is more related to HOW I might perform those tasks?