We're upgrading the software on two servers and, in the process, also migrating from Windows Server 2008 to Windows Server 2012. All servers are VMWare images.

During the migration, we will have a temporary server on which to install the new O/S and software, while the old server is used for Business As Usual. After the migration and UAT, the old servers (VMWare images) will be decommissioned, and the new VMWare images will be linked to our current server.

My question: is it possible to use the same machine names for the new servers? This would make migration of the software much easier. During the migration, I'm happy to access (RDP/MSTSC) the new environment via IP address only, but we would need to be able to copy files from the old server(s) to the new one, so we would need network connectivity between the machines.

Yep, I can ask my IT department this question, but I'd like a 2nd opinion / 3rd party confirmation whether this is technically possible.


  • You forgot to mention if the hosts are (meant to be) domain members. – the-wabbit Jul 7 '14 at 2:01
  • Sorry, yes after the migration, the new VMWare images will be domain members. – Scott Jul 7 '14 at 2:43

Name resolution only one possible problem. You can't join both machines to the same domain. One or the other will have a broken domain trust relationship as a result of joining the other.

Your only option would be to get a copy of Active Directory (AD) virtualized in your UAT environment and testing with it. This is likely a non-trivial request to your IT department (and they'll probably look at you funny if you ask for it), but it is feasible.

When I've had critical production migrations that need to be tested, complete with AD, I've done this kind of thing. It takes making changes temporarily in the production domain (to add the virtual DC, allow it to replicate, then perform a metadata cleanup after "forcefully" removing it from the domain), and a lot of admins won't be alright with that.


If the two sets of machines don't need to be joined to the domain at the same time then you're fine. NetBIOS name resolution would be problematic if they're in the same IP subnet, so make sure they're in different subnets and that won't be a problem.

As far as copying files between the machines goes, so long as you have arbitrary TCP communication between the machines you can always use the IP addresses in UNCs to access the other sets of machines even of they have conflicting names.

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  • Is it possible to have the new machines in a different subnet, not defined to AD and DNS, yet accessible from my desktop machine via IP address, and not interfere with the BAU machine? Sorry, this issue is above my existing networking skills, so apologies if the questions are stupid. It's not the end of the world if the new machines are named differently, but if they were the same, we could copy existing config files from the current machine to the new one to speed up the software migration. The new machine names will require URL changes by the end users for the web components. – Scott Jul 7 '14 at 4:07
  • To clarify: the old and new machines don't need to be in AD at the same time, but I need to 1) be able to RDP into the new machines and 2) copy files across the network from the old to new machines. The new machines would be added to AD only after the old ones are decommissioned. – Scott Jul 7 '14 at 4:09
  • I dropped on an edit. – Evan Anderson Jul 7 '14 at 4:34
  • The NetBIOS broadcast name resolution problem can be circumvented by modifying local firewall rules on both machines to prevent reception of broadcasts to ports 137/tcp and 138/tcp. – the-wabbit Jul 7 '14 at 7:53
  • Thanks Evan and wabbit, I really appreciate your input. I'll read up on subnets (I've only ever done on my home network). Regardless, you've given me enough info to confidently request this of my IT department. I'm too new here to upvote but I've marked your reply as the answer. Thanks again... – Scott Jul 7 '14 at 8:47

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