How to add 2nd name to AD server?

Question

Windows Server

Good. The situation is this, a certain number of machines are driven into AD. The domain name - ad.orgname is successfully resolved via DNS and everyone is happy.
However, now there is a need to make the domain available also at ad.org.ru. I will register DNS, but the question is how to make the domain controller accept and process such requests?
And most importantly, users should be able to work regardless of the login ( @ad.orgname or @ad.org.ru).
How can this be implemented? To register ad.orgname on those DNS - there are no options. As an option, for example, I see renaming the entire AD, but I want to avoid this.

Answer 1

For the first - add an Alternative Name for the domain controller - through the command "netdom computername currentDC FQDN /add:newDCName FQDN"
For the most important, add an additional UPN to the domain.
Well, the second DNS zone ad.org.ru will need to be created.