DHCP Failover stuck in Partner Down Pending after maintenance

Question

I am asked to force the state update via netsh or PowerShell but my DHCP Failover state is stuck in Partner Down Pending or can't be transitioned to full Partner Down. This is on my Server-B after a planned maintenance outage on Server-A and client IP scope exhaustion occurred.

Answer 1

Hello Jenifer, thank you for posting in the Microsoft Q&A community.

This behavior typically occurs due to how Windows Server DHCP Failover handles state transitions and the Maximum Client Lead Time (MCLT) timer. While in Partner Down Pending or Communication Interrupted state, Server-B is restricted to leasing IP addresses only for the duration of the MCLT and cannot immediately allocate the full IP pool reserved for Server-A. If the automatic state transition timer fails to complete or encounters a deadlock (often caused by RPC session locks or a state mismatch during the maintenance period), Server-B cannot transition to full Partner Down mode, causing local IP pool exhaustion under client demand.

You can manually force Server-B into the PartnerDown state using PowerShell. This allows Server-B to assume full authority over the entire IP range and immediately relieve scope exhaustion.

Run the following command in an elevated PowerShell session on Server-B:

Set-DhcpServerv4Failover -ComputerName "Server-B" -Name "Your-Failover-Name" -PartnerDown -Force

Once Server-B transitions to Partner Down, it will begin serving IP addresses from the entire pool.

After Server-A is fully online and verified reachable, force a state replication sync from Server-B:

Invoke-DhcpServerv4FailoverReplication -ComputerName "Server-B" -Name "Your-Failover-Name" -Force

If the state transition command continues to throw errors or remain stuck, breaking the failover relationship temporarily will remove the operational restrictions on Server-B and convert the scope into a standalone active scope.

1. Remove the failover configuration from Server-B:

      Remove-DhcpServerv4Failover -ComputerName "Server-B" -Name "Your-Failover-Name" -Force
   

2. Restart the DHCP Server service to clear any active RPC locks or memory cache:

      Restart-Service -Name DhcpServer
   

3. Once Server-A is fully restored and online, verify that any orphaned failover references are removed on Server-A, and then re-establish the failover relationship between Server-A and Server-B.

Microsoft Official Documentation:

• Set-DhcpServerv4Failover (DhcpServer)
• Invoke-DhcpServerv4FailoverReplication (DhcpServer)
• DHCP Failover Modes & Transition States