Apologies in advance for this naive question: Do I need a domain name that I use solely for DNS purposes when hosting multiple websites on one IP address? I've been learning ISPConfig 3 on an Ubuntu 16.04 server (virtual box on windows dektop). In following the tutorials I gave my server the name testserver.test.com and the names servers ns1.testserver.test.com and ns2.testserver.test.com respectively. I gave the hosted websites the names of actual domains I own. This would imply that with a real world implementation needs a new domain name to use in place of test.com. Is this necessary or can I safely use one of the hosted domain names as my name server as well as for a website. If it is possible is it bad practice to do so? Thanks for any help.