In previous versions of Windows, if you wanted to have fault tolerant DHCP, you had to rely on technologies like Failover Clustering or configuring split scopes. In Windows Server 2012 we have a new way to achieve this…Failover DHCP.
Failover DHCP allows you to replicate one or more DHCP scopes to another DHCP server. Here I have two virtual machine configured to be DHCP servers. Notice that only one has a scope.
Right clicking on the scope displays the option for ‘Configure Failover’. The interface for this is quite simple and allows us to select a server to replicate with, decide between load balancing or hot standby (like a hot spare), and other options.
Now you can see the scope on both DHCP servers.
This is a very quick and very simple way to have fault tolerance for your DHCP servers without having to configure and maintain a larger clustering technology. It is limited to IPv4 and you can only have two nodes, but sometimes that is all you are after.
You can also remove the partnership between the servers by right clicking on the scope and selecting ‘Deconfigure Failover’. Whichever server you performed this operation on, would take over the scope. This means you could use this technology to quickly move a scope or set of scopes from one server to another.