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James Hurley
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DC that is AD, DHCP & DNS not starting until DC2 is online

Hi Experts.

We had a major power outage last week and my server room all shutdown nicely as it should but, when rebooting everything we came across a slight issue. I booted our main DC that is AD, DHCP & DNS. I noticed that it was not serving DHCP address and on closer inspection there were a few errors, notibly that 'The DHCP service failed to see a directory server for authorization.'


'The DNS server is waiting for Active Directory Domain Services (AD DS) to signal that the initial synchronization of the directory has been completed. The DNS server service cannot start until the initial synchronization is complete because critical DNS data might not yet be replicated onto this domain controller. If events in the AD DS event log indicate that there is a problem with DNS name resolution, consider adding the IP address of another DNS server for this domain to the DNS server list in the Internet Protocol properties of this computer. This event will be logged every two minutes until AD DS has signaled that the initial synchronization has successfully completed'

My issue is that my DC2 is a virtual DC. And i have to boot my SAN, ESX Hosts and then (because DNS isnt working) go directly to my ESX host and then start DC2 a process that can take at least 15 mins.

After a few minutes i restart theses services on DC1

Active Directory Domain Services
DHCP Server

Then it all kicks into life and starts serving address again.

Surley my DC1 should be able to authorise itself against its AD, and then DHCP & DNS should just work, why would it be waiting for DC2?

Any suggestions?
Windows Server 2008Active DirectoryDHCP

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James Hurley

8/22/2022 - Mon

so why isn't dc2 set to start when the host does

I would guess that all of the FSMO roles are on DC2, if you move them to DC1 then the problem would not exist.

What are the DNS settings on the NIC on DC1  ?
James Hurley

Hi ArneLovius,

I have checked and all the FSMO roles are on DC1. The DNS settings on the local NIC are and then DC2.
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James Murphy

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James Hurley

Putting this down to coincidence. Haven't been in a position to replicate since this happened.