SYSVOL Stopped Syncing to the other Domain Controllers

I had 2 Domain controllers…

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I had 2 Domain controllers that stopped replicating their SYSVOL to each other. These are some of the commands used to understand what is happening and then to get it working again.

Learnings

  • Edit your Group Policies on the PDC / Operations Master (see the netdom query fsmo) to figure out which DC is the PDC
  • You can quickly check if your replication is working by viewing the contents of the policies folder on each of the domain controller and sorting by Date Modified descending new policies will show up on all domain controllers if DFSR is working.
  • If new Group Policies you create don't appear on each DC's SYSVOL Share you have a SYSVOL sync problem.

What is the current SYSVOL replication state of the domain controllers in the domain?

Run this command before you attempt to promote a new Domain Controller and make sure the current domain controllers are showing state 4.

For /f %i IN ('dsquery server -o rdn') do @echo %i && @wmic /node:"%i" /namespace:\\root\microsoftdfs path dfsrreplicatedfolderinfo WHERE replicatedfoldername='SYSVOL share' get replicationgroupname,replicatedfoldername,state

Healthy replication state 4 = Normal.

DC01
ReplicatedFolderName  ReplicationGroupName  State
SYSVOL Share          Domain System Volume  4

DC02
ReplicatedFolderName  ReplicationGroupName  State
SYSVOL Share          Domain System Volume  4

DC03
ReplicatedFolderName  ReplicationGroupName  State
SYSVOL Share          Domain System Volume  4


What you might see when your SYSVOLS are out of synch and they refuse to replicate

I had to demote a new DC, run an authoratative synchronization (see below) and re promote it because I promoted it while the SYSVOLS synch status of the other two DC's were in state 2.

Your newly promoted DC won't be able to replicate SYSVOL and create the NETLOGON and SYSVOL Shares if it can't replicate from the current DC's

Possible replications states are
  • 0: Uninitialized
  • 1: Initialized
  • 2: Initial synchronization
  • 3: Auto recovery
  • 4: Normal
  • 5: In error state
  • 6: Disabled
  • 7: Unknown

How to view the Sysvol DFSR Backlog between servers

There should be no or just the very latest Group policy files still waiting to replicate as output. If you have good connections to your DC's and simple replication structure no output is expected.

Command line using dfsrdiag

 Get-DfsrBacklog -SourceComputerName DC01 -DestinationComputerName DC03 -RgName "Domain System Volume" -RfName "SYSVOL Share"

Run an Authoritative Synchronization to get the replication state back to 4

If the Sysvol on your PDC has all its SYSVOL login scripts and policies and you just want to push them to all your other DC's you will need to follow "How to perform an authoritative synchronization of DFSR-replicated sysvol replication (like D4 for FRS)"

Before doing this take a backup copy of C:\Windows\SYSVOL or wherever your sysvols are on each domain controller.

https://learn.microsoft.com/en-us/troubleshoot/windows-server/group-policy/force-authoritative-non-authoritative-synchronization#how-to-perform-an-authoritative-synchronization-of-dfsr-replicated-sysvol-replication-like-d4-for-frs

See the current replication status

repadmin /replsummary
Replication Summary Start Time: 2023-10-31 11:33:56

Beginning data collection for replication summary, this may take awhile:
  ......


Source DSA          largest delta    fails/total %%   error
 DC01                46m:03s    0 /  10    0
 DC02                46m:03s    0 /  10    0
 DC03                38m:53s    0 /  10    0


Destination DSA     largest delta    fails/total %%   error
 DC01                34m:01s    0 /  10    0
 DC02                38m:53s    0 /  10    0
 DC03                46m:03s    0 /  10    0

Replication status with more detail

repadmin /showrepl

Repadmin: running command /showrepl against full DC localhost
Azure\DC03
DSA Options: IS_GC
Site Options: (none)
DSA object GUID: 0cc2f0d6-7711-4e6d-b27b-0484e54a51f4
DSA invocationID: 624cf2c5-3689-4a8e-8c50-d7e7eca7cde2

==== INBOUND NEIGHBORS ======================================

DC=TOGGEN,DC=LOCAL
    Azure\DC02 via RPC
        DSA object GUID: 6e27820c-a290-40d2-8caf-d00f991a0360
        Last attempt @ 2023-10-31 11:34:34 was successful.
    Azure\DC01 via RPC
        DSA object GUID: 1a62bae0-0f6a-41d2-ba0d-ebb0c835d210
        Last attempt @ 2023-10-31 11:35:28 was successful.

CN=Configuration,DC=TOGGEN,DC=LOCAL
    Azure\DC02 via RPC
        DSA object GUID: 6e27820c-a290-40d2-8caf-d00f991a0360
        Last attempt @ 2023-10-31 10:47:53 was successful.
    Azure\DC01 via RPC
        DSA object GUID: 1a62bae0-0f6a-41d2-ba0d-ebb0c835d210
        Last attempt @ 2023-10-31 10:47:53 was successful.

CN=Schema,CN=Configuration,DC=TOGGEN,DC=LOCAL
    Azure\DC02 via RPC
        DSA object GUID: 6e27820c-a290-40d2-8caf-d00f991a0360
        Last attempt @ 2023-10-31 10:47:53 was successful.
    Azure\DC01 via RPC
        DSA object GUID: 1a62bae0-0f6a-41d2-ba0d-ebb0c835d210
        Last attempt @ 2023-10-31 10:47:53 was successful.

DC=DomainDnsZones,DC=TOGGEN,DC=LOCAL
    Azure\DC01 via RPC
        DSA object GUID: 1a62bae0-0f6a-41d2-ba0d-ebb0c835d210
        Last attempt @ 2023-10-31 10:47:53 was successful.
    Azure\DC02 via RPC
        DSA object GUID: 6e27820c-a290-40d2-8caf-d00f991a0360
        Last attempt @ 2023-10-31 10:47:53 was successful.

DC=ForestDnsZones,DC=TOGGEN,DC=LOCAL
    Azure\DC02 via RPC
        DSA object GUID: 6e27820c-a290-40d2-8caf-d00f991a0360
        Last attempt @ 2023-10-31 10:47:53 was successful.
    Azure\DC01 via RPC
        DSA object GUID: 1a62bae0-0f6a-41d2-ba0d-ebb0c835d210
        Last attempt @ 2023-10-31 10:47:53 was successful.

Force Replication of Domain Controllers

repadmin /syncall /AdeP

Which domain controller holds the FSMO (Flexible single master of operations) Roles

netdom query fsmo

Output

Schema master               DC01.TOGGEN.LOCAL
Domain naming master        DC01.TOGGEN.LOCAL
PDC                         DC01.TOGGEN.LOCAL
RID pool manager            DC01.TOGGEN.LOCAL
Infrastructure master       DC01.TOGGEN.LOCAL
The command completed successfully.

View a list of installed HotFixes or KB patches

wmic qfe list

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