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I have a Win2K8 node with dns suffix vm100.eng.mycompany.com. And I want to join it to an AD domain (which uses a different DNS suffix. ad.mycompany.com) but I don't want the node's primary dns suffix to change, and therefore change its FQDN to vm100.ad.mycompany.com. Is this possible?

EDIT Reword and removed the background info and alternate solution since it was confusing people.

Michael Closson
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    You say `" I don't want the node's FQDN to change to vm100.ad.mycompany.com"` and then you also say `"Another option it to make it so that the windows VMs are assigned a name *.ad.mycompany.com."` Which is it? – MDMarra Dec 12 '12 at 18:45
  • @MDMarra. Its the first. – Michael Closson Dec 12 '12 at 19:48

3 Answers3

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As others have said, it is not clear what you want but, taking you literally:

I have a Win2K8 node with FQDN vm100.eng.mycompany.com. And I want to join it to an AD domain (ad.mycompany.com) but I don't want the node's FQDN to change to vm100.ad.mycompany.com. Is this possible?

Try, right-clicking My Computer and choose Properties. From this dialog you should be able to get to the dialog that allows you to change your Computer Name. From that dialog, click the Change button (i.e to rename or change its domain). From there, click the More button.

There is a tickbox there that says 'Change primary DNS suffix when domain membership changes'.

If that is what you want not to happen, unticking this should do the job.

But you might want to change your process so that this transition is not as painful. One of the following might do it:

  • change your batch processor to resolve the IP address of the *.eng.mycompany.com address first, and attempt all reconnections to that IP, instead. You might need to take this further (e.g. if your DHCP leases are very short) and query the MAC through Netbios, then fetch the new IP by querying ARP

  • change your VMs so that, on startup, they make a call to the cloud handler, sending their name, IP and FQDN to a register. Then, if your batch processor 'loses' the machine it is working on, it can make another call to the cloud processor asking for the FQDN of the machine with the registered name (which you might derive from the left-most chars in the FQDN, up to '.')

  • expose a user account and pre-configure it on the VMs, so they can access the shared storage without having to join the domain

jimbobmcgee
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Uh, no.

FQDN == Fully Qualified Domain Name.

A Fully Qualified Domain Name is the host's hostname with the domain name appended.

Sounds to me like you don't quite understand how DNS works, which is making it hard to figure out what's really going on here, honestly.

EDIT:

As pointed out by @jimbobmcgee 's answer, it is possible to keep the DNS suffix the same when joining the computer to your AD domain, but DNS suffixes and FQDNs are different things, and I think you're confusing the two, which is causing issues in addressing your question.

There's no reason that you can't have the FQDN change and still do what you're doing. (I think, based on your description, anyway.) The easiest solution would be to setup aliasing in AD DNS so that vm100.ad.mycompany.com and vm100.eng.mycompany.com point to the same IP. In all honesty, it seems to me like your system's a little broken/misconfigured if it's running against a different domain/subdomain than the one you're actually using, and I'd work on fixing that, but there are any number of quick fixes to alleviate the symptom you're encountering.

HopelessN00b
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    The reason that I don't want the FQDN to change is because there is an application in the system that expect the machine to have the eng suffix. Yes, change the app is one option. But it would require some code change. – Michael Closson Dec 12 '12 at 20:40
  • @MichaelClosson Well, there's no way to keep the FQDN the same when you join a different domain. Closest you can come is faking it with DNS entries and [an incorrect] DNS suffix. So either join the `.eng...` domain, or change the code/app. Oh, and kick the app developer in the fun bits for hard-coding that, which seems especially short-sighted and lame-brained. – HopelessN00b Dec 12 '12 at 20:51
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    Oh, I understand your confusion now. While its true that FQDN and dns suffix are different, they are **very** much related. If the dns suffix changes, then what the node thinks its FQDN is will also change. And this was the problem, there was no hard-coding of anything. One system was expecting vm100.eng.mycompany.com, but the VM was reporting itself as vm100.ad.mycompany.com. And no, comparing short hostnames is not and option since the system supports multiple administrative domains. – Michael Closson Dec 13 '12 at 16:58
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What you actually want and are trying to do is unclear, but it seems to be that you can accomplish what you want by having part of your automated process register a record in the eng.mycompany.com zone on behalf of your VM, so that it will be reachable by either vm100.eng.mycompany.com due to the static record that you just created, and vm100.ad.mycompany.com because of the dynamic record that it registers with the DCs.

It sounds like your requirements can all be met by manipulating the DNS zone in question, and doesn't really require anything from the host.

And just to answer the actual question, Yes, you can change this in the Advanced System Settings > Computer Name > More > Primary DNS Suffix of this computer settings, but it's not going to automatically start registering records in the zone that you set that to.

MDMarra
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