Daily Archives: November 16, 2010

Error : The specified DHCP client is not a reserved client.

While creating a reservation in a DHCP scope (Windows 2008 R2) I received the error mentioned.

After some investigation I discovered that Windows 2008 R2 doesn’t allow reservations that are not in the scope, although the¬†subnetmask (for example ¬†is big enough. Changing the subnetmask isn’t an option, so you have to delete and re-create the scope.

You can export the settings with the following command :

netsh dhcp server ip-adres server scope X.X.X.X dump > c:\dump,txt

Then edit the subnet mask

and import the scope with the following command :

netsh exec c:\dump.txt

Using Windows 2003 and Windows 2008 (not R2) it is possible to add reservations within the subnetmask but out of the DHCP scope!