I'm hoping someone can confirm my observations because I'm questioning my memory…
The title kind of says it all. While working rapidly on deploying a number of similar systems, it appeared that we were able to create systems with the same name and Active Directory allowed us to add them to the domain.
Problem was that one of the machines would no longer "see" the domain, saying it wasn't able to see it anymore.
I removed a machine from the domain and then re-added it with a variation to the name; am I misremembering something, or is it possible to add two machines to AD and effectively drop the other machine from the domain? Am I wrong in thinking this is something that AD shouldn't allow in the first place? I thought it would give a warning, as AD does when you try adding a username that already exists withing the AD structure.
Best Answer
No, computer names must be unique. When you added the second computer with the same name, windows changed the sid in the AD database that goes with that name making the first machine not able to talk to the domain.
To keep the first machine on the domain, you'd need to remove the second machine from the domain, then readd the first machine back to the domain. Then add the second machine to the domain under a second name.
To keep the second machine on the domain, take the first machine from the domain, rename it and add it back to the domain under the new name.