DHCP Server - Migrate Leases only

Question

_{Wednesday, September 3, 2014 9:38 AM}

Hi all,

Not sure if this is possible from my reading but hoping it is...Here is the situation I am looking to consolidate a number of DHCP servers to a central 2012 failover pair.  As part of this migration I am also going to be changing the DNS options on every scope (couple of hundred scopes) from the exising DNS servers to a new set.

My thinking is to:

1. export the scopes now prior to the actual migration (using netsh on the 2003 DHCP servers),
2. import them into a single 2012 DHCP server (using netsh on the 2012 DHCP server)
3. use the export-dhcpserver powershell command to export the config to xml (for editing the DNS servers)
4. find and replace all of the old DNS option 6 entries with new DNS server IPs - save the new xml file
5. clear the DHCP scopes (Get-DhcpServerV4Scope | Where-Object –FilterScript { $_.State -Eq "active" } | Remove-DhcpServerv4Scope -Force -Passthru)
6. REPEAT FOR EACH LEGACY DHCP SERVER (x8)
7. Import the new xml configs (using import-dhcpserver, not allowing existing scopes to be overwritten)

At this point i will have all scopes imported to the new 2012 server with the new DNS settings and I can then configure a load balanced failover pair....

My question is - now that I have prestaged all of the scopes, come the actual migration all I really need to move across are the existing leases - is it possible to just import the leases from the XML file?  I realise I may need a third DHCP server to generate the XML files but that is fine I can just spin up a VM....

Thanks All!!!

All replies (1)

_{Thursday, September 4, 2014 9:03 AM ✅Answered}

Hi,

According to your description,the question is if it is possible to import the leases from the XML file.

In fact,we don't need to import the leases,because the lease generation and renewal process is initiated by the DHCP client.

In addition,we can use the methods below to remove old scopes without disrupting DHCP service to clients on the subnet.

• Create a replacement scope for the subnet before the old scope is deactivated. You can create a replacement scope on a different DHCP server or on the same server.
• Deactivate a DHCP scope before removing it. After a scope is deactivated, it does not acknowledge lease or renewal requests. DHCP clients will be unable to renew their leases from the deactivated scope and the original server, so the clients will seek new leases from an available DHCP server.

Note: Membership in the Administrators or DHCP Administrators group is the minimum required to complete this procedure.

For more details about DHCP Server Migration,please refer to links below,

DHCP Server Migration Guide

http://technet.microsoft.com/en-us/library/dd379535(v=WS.10).aspx

Migrate DHCP Scopes

http://technet.microsoft.com/en-us/library/dd183693(v=WS.10).aspx

Best Regards,

Tina