In the DHCP snap-in, reconcile the DHCP scope.
To perform these procedures, you must be a member of the Administrators group, or you must have been delegated the appropriate authority.
To reconcile a DHCP scope:
At the DHCP server, click Start, point to Administrative Tools, and then click DHCP.
In the console tree, click the scope you want to configure.
On the Action menu, click Reconcile.
In the Reconcile dialog box, click Verify.
If the verification indicates that the scope is consistent, click OK.
If the scope is not consistent, select the displayed IP addresses that need to be reconciled, and then click Reconcile to repair inconsistencies.
Ensure that there are no discrepancies in the options, classes, or other information configured for each scope.