"...Dynamic Host Configuration Protocol (DHCP) failover in Windows Server 2012 is a new method for ensuring continuous availability of DHCP service to clients..."

 

This new DHCP functionality is superb: resilient, robust and ripe for automation. In 2013 I produced a plan for a PowerShell-driven migration of a very large Windows Server 2003 DHCP split-scope configuration to a Windows Server 2012 DHCP failover platform.

The plan needed to determine the DHCP failover mode. There are two options: Hot Standby and Load Balance.

 

Hot Standby

One partner is 'Active' the other is on 'Standby'. You can figure the % of addresses reserved for the 'Standby' server.

 

Load Balance

Both partners share the active load. Typically, you would split the relationship 50 / 50.

 

What if you wanted to switch from one failover option to the other? In v3 of PowerShell, this wasn't possible - you'd have to use the GUI.

 

 

In v4 of PowerShell, the Set-DhcpServerv4Failover cmdlet now has the -Mode parameter. This will accept a value of  LoadBalance or HotStandy.

Set-DhcpServerv4Failover -ComputerName HALODC02 -Name "HALODC02_HALODC01_FAILOVER" -Mode LoadBalance

 

 

The -ComputerName is the target DHCP server and the -Name is the name of the failover relationship.

  

Upgrade to Windows Server 2012 DHCP today! Hurry, whilst stocks last!