DHCP servers report different failover states or do not replicate lease information in a Windows Server 2012-based DHCP failover relationship

Symptoms
You experience one or more of the following issues when you use Dynamic Host Configuration Protocol (DHCP) failover in Windows Server 2012:
  • Two DHCP servers in a failover relationship report different failover states. This issue occurs even though both servers are connected to the network. 
  • Some lease information is not replicated successfully between the two DHCP servers even though both servers report a typical failover state.  
Cause
These are known issues with DHCP failover in Windows Server 2012. These issues occur when the following conditions are true:
  • Existing scopes are migrated to Windows Server 2012 by using netsh dhcp server export and netsh dhcp server import commands. Or, an existing DHCP server is upgraded to Windows Server 2012.
  • A scope has one or more inactive reservations when the scope is migrated or when the DHCP server is upgraded.
Resolution
To resolve these issues, apply the cumulative update package that is described in the following article in the Microsoft Knowledge Base:
2756872 Windows 8 Client and Windows Server 2012 General Availability Cumulative Update
Note To resolve the issues in an existing failover relationship, delete the relationship before you apply the update package, and then re-create the failover relationship. These issues do not occur if a failover relationship is created after you apply the cumulative update package.
Workaround
To work around these issues, use the following Windows PowerShell commands to migrate scopes to Windows Server 2012:
  • Export-DhcpServer
  • Import-DhcpServer
The following is a sample set of commands:
Export-DhcpServer $env:SystemRoot\System32\Dhcp\Temp.txt -LeasesImport-DhcpServer -BackupPath $env:SystemRoot\System32\Dhcp\Backup -File $env:SystemRoot\System32\Dhcp\Temp.txt -ScopeOverwrite -LeasesRestart-Service DHCPServer
More information
These issues do not occur if scopes are migrated by using the Windows PowerShell commands Export-DhcpServer and Import-DhcpServer.
Properties

Article ID: 2751456 - Last Review: 08/28/2013 08:24:00 - Revision: 2.0

Windows Server 2012 Datacenter, Windows Server 2012 Standard

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