S2k3 DHCP Migration Ball-Ache

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Afternoon OCUK.

I'm faced with a pain in the butt scenario which I'd appreciate help with.

I have 1x 2003 utility server that will become virtual (off site) which is serving DHCP to a Voice network. One of those things that was set up in a hurry and remained that way.

I also have a 2003 DC running DHCP for the Data networks, which is remaining on-site & physical. The plan is to move the voice scope onto that server to centralise DHCP and keep it local. DHCP relay is already configured for other VLANs and works fine. The intention would be to use that for the voice scope.

On the face of it things are simples* but infinite leases mean the phones with IPs currently issued by the old server will not renew from the new server, and any new leases will conflict with them as the new server isn't aware of any leases previously dished out by the old server. (270 odd of them)

Backup and restore of DHCP is out of the question as I've tested that on a lab box and the restore overwrites any scopes that exist on the destination server. Parallel scopes is out of the question as there are >260 leases currently and only 500 addresses in the network.

What I wanna do is restore just one scope, OR create a new scope and export then import the leases from the old box.

^Sounds perfectly sane and doable, but damned if I know how/can find a KB article on how. I can't be the first person that's needed to consolidate a DHCP server like this surely?

My alternative; create duplicate scope, deactivate old one, some time late at night when things are less busy (it's a hospital so 24 hour operation) reboot or disable + enable PoE on all the switches to leave the phones searching for DHCP. Then turn on the new scope..... Which will sure as hell NOT have infinite leases on it.

That however, has it's own caveats such as hybrid PoE switches doing more than just voice, getting the permission to take down the phone system in it's entirety for 10 minutes at any time of day + crash call stuff and all the risk assessments that go with it. It'll work but it's not elegant and it's a total ballache on top.

Ideas mentlegen?
 
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1 - Punch Daveo for keeping it that way :P

2 - Tried an export/import?

C:\>netsh dhcp server export c:\dhcp.txt all
C:\>netsh dhcp server import c:\dhcp.txt all

not sure if that's good enough, might be able to export it to the TXT file, edit it then do the import so it doesn't overwrite the rest of the DB?

Did you get your UAT set there for this? never done it this way so not sure if it will work or not

-GP
 
The fact it's stayed that way isn't really anyone's fault. It worked fine and up till now there's been no need to touch it. The location of the scope is no issue at all compared to the use of infinite leases.
Rather punch the Telecoms guys for telling us we needed infinite leases else extensions would unregister themselves, when I've changed phones from static IP to DHCP on a completely different subnet only to have them boot straight back up with their old extension and config preserved. Proving that to be steaming BS.

I'll try the text import export on a Lab VM and see what happens. Tbh I thought that was only used on pre 2000 DCs that didn't support backup and restore into AD. Which may mean it'll actually work....!
 
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BUZINGA! Someone just earned themselves a pint.

God bless "/?"


Confirmation in case anyone else needs to do it:

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Exported config using: netsh dhcp server test-srv export c:\temp\dhcp.txt 172.17.254.0
Copied the file to the test box
Created the test scope on the text box
Imported the file using: netsh dhcp server test-srv import c:\temp\dhcp.txt 172.17.254.0
Restarted DHCP server service and hey presto, see above with the leases all still intact on the new server :)
 
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