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DHCP authorization

snyderkv
snyderkv used Ask the Experts™
on
EE,

Just wondering how AD keeps track of DHCP authorization since we are migrating from physical to virtual and then changing the iP Address and then the name. The server itself will remain the same, but the MAC will change once virtual.

When moving from one host to another, I've been able to keep the authorization by copying the DHCP folder and pasting it into the other new DHCP server directory. But not so sure about what we are trying to do here.

Any suggestions on moving this server to a new one without reauthorizing?
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JohnBusiness Consultant (Owner)
Most Valuable Expert 2012
Expert of the Year 2018

Commented:
DHCP hands out leases as needed. People will just get new leases when they log in. In my experience, there is nothing to do as it is automatic. ... Thinkpads_User
JohnBusiness Consultant (Owner)
Most Valuable Expert 2012
Expert of the Year 2018

Commented:
By the way, although I maintain that for the most part this is just automatic, there is a facility in DHCP in your server to back up (export) the DHCP database. Start -> Administrative Tools -> DHCP and then export is under the Action tab. Best thing to do is to go to Help and search for Export. Then read up on Backing up the DHCP database.

.... Thinkpads_User

Author

Commented:
Thinkpads, I have used the dhcp server command to export and import DHCP config successfully but only to a server with the same name and IP Address. Will the config even import to a different name and IP and stay authorized? I'd try this out right now if I had a test lab.
JohnBusiness Consultant (Owner)
Most Valuable Expert 2012
Expert of the Year 2018

Commented:
>>> Will the config even import to a different name and IP and stay authorized  <-- I am not sure of that. I only have one (two at most) machines in any given client that require special treatment. So when I have changed servers, the reconnection was automatic.  ... Thinkpads_User
Network Engineer
Commented:
AD has the list of authorized servers in AD. It does this via servername and possibly some other information (GUID?). I don't think that it uses any attribute of a machine installation that can change during your process, but I make no promises regarding the IP address change. Recently had to use adsiedit to clean up some old authorizations. I would need to dig into it to be sure.  

Why are you worried about keeping the DHCP server authorized? Don't you have rights to authorize/deauthorize DHCP servers? To avoid any issues, I recommend you deauthorize the server, make all of your changes, and then reauthorize it.  
JohnBusiness Consultant (Owner)
Most Valuable Expert 2012
Expert of the Year 2018
Commented:
Here is a Microsoft article to move the exported list to another server. I do not really need this function so I have not used it. But I am sure Microsoft knows what it is doing.

http://support.microsoft.com/kb/325473

.... Thinkpads_User
Sandesh DubeyTechnical Lead
Top Expert 2011
Commented:
There will be no issue if you are moving from from physical to virtual environment .

But for saftey take the backup of DHCP server.