How to add back Authorized DHCP servers?

Question

Dear All,

We are a DC in production that is still running on Windows Server 2012 R2. The issue is that we used DHCP tools from Windows 11 client machine, right-click on the DHCP icon and accidentally click "Unauthorize" on one of the servers on the list of Authorized DHCP servers under Manage Authorized Servers.

I didn't see how bad this is but how can we add it back to the Authroized DHCP servers list, and how to resume everything? I logged into that server let's called DC1, the DHCP service is still there and new machine can still get the IP address from it. When I right-click on this server, there is only Unauthorized option, but no Authorize, do we still need to re-authorize it?

Any advice would be really appreciated.

Answer 1

You could check it first. This example gets the list of all computers that run the DHCP server service which are authorized in the Active Directory domain.

Get-DhcpServerInDC

then if needed you can; This example adds an object in the Active Directory domain for the DHCP server service that runs on the computer that has the DNS name dhcpserver.contoso.com and the IP address 10.10.10.2, and authorizes the DHCP server service to serve DHCP clients on the network.

Add-DhcpServerInDC -DnsName "dhcpserver.contoso.com" -IPAddress 10.10.10.2

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