@scottalanmiller said in Active Directory Domain name:
But the absolute first, most basic rule of Active Directory is never, ever to make it the same name as your domain. Because AD requires DNS to work, it has to control whatever domain you set it to. So if you use a public domain name used for anything else, proper DNS cannot work. So, for example, your company website will not have an possible DNS entry for it because you made both your website AND your domain the same name and since the domain is mandatory, your website won't work.
/sigh - huh? This didn't become the rule until many many years after MS, All MS training for 2000 said use your real domain name, then for Windows 2003 (I think) they changed it to .local, then they dumped .local sometime after 2010.
All that said - I ran with a domain with my real domain name for nearly two decades. Did it cause split DNS issues of course it did - could I work around it - of course I could/did like like thousands of others.
But - if you are standing up something today - definitely use something completely unrelated to anything real or likely more simple - just use a subdomain of your real domain, such as ad.domain.com