As per Microsoft: "This event message indicates the possibility of an unauthorized server on the network. For the directory authorization process to work properly, it is assumed and necessary that the first DHCP server introduced on to your network participate in the Active Directory service. This requires that the server be installed as either a domain controller or a member server. Where you are either planning for or actively deploying Active Directory services, it is important that you do not select to install your first DHCP server computer as a stand-alone server". See MSW2KDB for more details.
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