How to Configuring and Installing High Availability of #DHCP using Windows Server 2012 #ws2012

How to Configuring and Installing High Availability of DHCP using Windows Server 2012

DHCP is often the one thing a IT Pro just runs as next, next, I agree,

But there is this big question Did you Know ?

DHCP failover in Windows Server 2012 enables administrators to deploy a highly resilient DHCP service to support a large enterprise without the challenges of the options discussed earlier. The main goals of the feature are the following:

  • Provide DHCP service availability at all times on the enterprise network.
  • If a DHCP server is no longer reachable, the DHCP client is able to extend the lease on its current IP address by contacting another DHCP server on the enterprise network.

The DHCP server failover feature provides the ability to have two DHCP servers provide IP addresses and option configuration to the same subnet or scope, providing for continuous availability of DHCP service to clients. The two DHCP servers replicate lease information between them, allowing one server to assume responsibility for servicing of clients for the entire subnet when the other server is unavailable. It is also possible to configure failover in a load-balancing configuration with client requests distributed between the two servers in a failover relationship.

DHCP failover in Windows Server 2012 provides support for a maximum of two DHCP servers, and the failover relationship is limited to IPv4 scopes and subnets. Network nodes using Internet Protocol version 6 (IPv6) typically determine their own IPv6 address using stateless IP auto configuration. In this mode, the DHCP server delivers only the DHCP option configuration, and the server does not maintain any lease state information. A high availability deployment for stateless DHCPv6 is possible by simply setting up two servers with identical option configuration. Even in a stateful DHCPv6 deployment, the scopes do not run under high address utilization, which makes split scope a viable solution for high availability.

So how do we start go to the add roles and add DHCP


clip_image002 The DCHP Role is now installed.

clip_image003[1] But Sure you can setup this with powershell easy and fast.

Add-WindowsFeature dhcp,rsat-dhcp

For the command line users, DHCP PowerShell provides the following PowerShell cmdlets for setting up and monitoring failover:

  • Add–DhcpServerv4Failover  – Creates a new IPv4 failover relationship to a DHCP server
  • Add–DhcpServerv4FailoverScope   – Adds the specified scope(s) to an existing failover relationship
  • Get–DhcpServerv4Failover   – Gets the failover relationships configured on the server
  • Remove–DhcpServerv4Failover   – Deletes the specified failover relationship(s)
  • Remove–DhcpServerv4FailoverScope – Removes the specified scopes from the failover relationship
  • Set–DhcpServerv4Failover   – Modifies the properties of an existing failover relationship
  • Invoke-DhcpServerv4FailoverReplication – Replicates scope configuration between failover partner servers

In powershell the installation of the two options is easy

powershell Add-WindowsFeature RSAT-DHCP

powershell Add-WindowsFeature DHCP

or both options at the same time.

powershell Add-WindowsFeature dhcp,rsat-dhcp

clip_image005 now that the roles are installed we can start.

Remember I use two servers in this demo and on both you should install the roles !

image  clip_image009 

The first two things I would do is change the database backup path to your location or just leave it to the designed location.

The Second part is change the binding of the DHCP server if you have multiple IP’s on the machine you should use only the IP address that the DHCP should use.


clip_image013       image

Configuring the Failover

the following example, two DHCP servers simultaneously provide IP addressing to clients on a single subnet.

Load sharing single subnet


clip_image015 clip_image017

If this step fails you need to install the dhcp role on the partner server





You can select the mode that you want to use load balance or hot standby

and you can adjust the scope as you desire

clip_image023 I do enable the authentication and use a shared secret


clip_image025  clip_image027

The wizzard does the configuration and you are done. the config is done on both servers.



in the failover properties you can see what partner there is and made some adjustments

press edit all the options are here in one screen to adjust the dhcp server


You can easy change from load balance mode to hot standby

clip_image035 If you want to make use of dynamic updates you need to configure a service/user account that can register items in the DNS server.

Most forgotten item !

in the advanced pane you can change this.

clip_image037 clip_image039


If you change the configuration it needs to replicate the config


Now we are all set ready to configure the scope and yes you need to authorize the server and activate the scope

clip_image002[4] clip_image004

clip_image006 clip_image008

The scopes on both servers

image  clip_image049

Go to the replication relationship and you can see the configuration.


But is is just two dhcp servers and how does the cluster fit in ?

still there are two servers to manage and it can be in two data centers but what if you already have a fine datacenter and you can use clustering.


Clustered DHCP servers


In this case I will not show you how to create a cluster. you can see this in my other blog posts.

clip_image051 clip_image053

Start up the failover manager and add roles and select the dhcp server and the wizard installs the dhcp role n the cluster.

you will need a dhcp server name and IP and a disk that holds the DHCP database.



Easy setup and easy to manage. there are multiple configurations for this and can be just the way you want this

Ensuring High Availability of DHCP using Windows Server 2012 DHCP Failover–ITPRO40922&WT.mc_id=aff-n-we-loc–ITPRO40922

Step-by-Step: Configure DHCP for Failover–ITPRO40922&WT.mc_id=aff-n-we-loc–ITPRO40922

Happy giving IP’s

  • Tag