Sorry for the late reply, only tonight I could think again about the Ubuntu Server.
Thank you very much for the replies. It works!
From Pmcdougl, I learned the file (/etc/hosts) and machine (not the server) I needed to modify. I still do not know what “dns A-Record” is, but Till Brehm helped with “server1.example.com pointing to your IP address”.
Also, searched in the forum, but did not find posts with, perhaps a newbie like me still have much to learn before even knowing what to search for.
Please, any suggestions of addresses where I can learn more, would be much appreciated, it seems that I will get more and more involved with this passionate subject.