Migrate DHCP from 2003 to 2008

Bleek · 27 Apr 2010 at 15:26

We've followed the Microsoft export/import method for moving DHCP from Windows 2003 to 2008 but the 2008 box won't dish out addresses.

The 2008 says it's up, is authorized and doesn't have any errors but no addresses are being dished out.

Any idea?

Do we need to turn off the 2003 box and not just disable the scopes?

edscdk · 27 Apr 2010 at 15:31

maybe the 2003 box is just faster, just stop the service and reboot a workstation (to see if the 2008 give it an address)?

worst case restart teh service and carry on investigating??

paradigm · 27 Apr 2010 at 15:41

What's the network topology? Are the clients on the same subnet as the DHCP server? Are the IP addresses of the old 2k3 box and the new 2k8 box different? Have you got the IPv4 Container bound to an adapter under "Properties > Advanced > Bindings"?

Bleek · 27 Apr 2010 at 15:51

None of the clients are on the same vlan as the servers, both boxes are still up and have different IP addresses, I'm testing one scope on the 2008 box, disabled that same scope on the 2003 box. Scope doesn't work now.

Bindings are correct, one NIC/address selected.

paradigm · 27 Apr 2010 at 15:53

If none of the clients are on the same vlan, have you added an ip helper-address to the switch/router config that handles your inter-vlan routing?

If this is cisco hardware then:

configure terminal
interface vlan xx (where xx = relevant vlan number)
ip helper-address x.x.x.x (where x.x.x.x is the IP address of your new 2k8 DHCP server)

Laser402 · 27 Apr 2010 at 22:20

paradigm said:
If none of the clients are on the same vlan, have you added an ip helper-address to the switch/router config that handles your inter-vlan routing?

If this is cisco hardware then:

configure terminal
interface vlan xx (where xx = relevant vlan number)
ip helper-address x.x.x.x (where x.x.x.x is the IP address of your new 2k8 DHCP server)

That sounds like the solution

Bleek · 28 Apr 2010 at 10:29

Why would DHCP work previously without that?

Is the issue that the original 2003 server is still 'authorized' in AD and therefore machines are still going to it before the new 2008 server? Does AD publish the DHCP server? Would I be best just to un-authorize the 2003?

paradigm · 28 Apr 2010 at 11:28

Bleek said:
Why would DHCP work previously without that?

It wouldn't. There must have either been an ip helper-address listed for the old DHCP server, or you had your router set to be a DHCP relay for the old DHCP server.

Without one or the other, it wouldn't work cross subnets.

Bleek · 28 Apr 2010 at 12:52

paradigm said:
It wouldn't. There must have either been an ip helper-address listed for the old DHCP server, or you had your router set to be a DHCP relay for the old DHCP server.

Without one or the other, it wouldn't work cross subnets.

Ok, thanks for that - I'll get on to the WAN team.

Bleek · 28 Apr 2010 at 15:06

paradigm said:
It wouldn't. There must have either been an ip helper-address listed for the old DHCP server, or you had your router set to be a DHCP relay for the old DHCP server.

Without one or the other, it wouldn't work cross subnets.

You were ****-on.

Had the cisco config fired over and 20 helper entries for the DHCP server, sorted.

Thanks!

paradigm · 28 Apr 2010 at 15:07

Glad I could help