Step by Step Guide : DHCP Failover in Server 2012 R2
After few month i gone missing / not updating my blog with my Step by Step, let continue today with DHCP failover in Windows Server 2012 R2.
DHCP failover is a new feature on the Windows Server 2012.
It provides the following features:
- 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 serve IP addresses and option configuration to the same subnet or scope.
DHCP failvoer in Windows Server 2012 provides support for a maximum of two DHCP servers, and the failover relationship is limited to IPv4 scopes and subnets.
So let begin with the process.. ** i assume most of you already know how to install DHCP Services on the Windows Server 2012 R2.**
1 – Right Click IPv4 and click Configure Failover…
2 – On the Configure Failover introduction page, confirm the Available scopes and click Next…
3 – Next, on the Specify the partner server to use for failover page, click Add Server and choose your 2nd DHCP Server.
4 – Next, confirm that 2nd DHCP Server IP address listed in the Partner Server box and click Next…
5 – On the Create a new failover relationship box, there are some configuration that you need to take point :
Relation name : Each relationship name is required to be unique on a server.
Maximum Client Lead Time : It defines the temporary lease period given by the failover server to a new client.
Mode : There are two modes for DHCP failover which are “Hot Standby” and “Load balance“.
In hot standby mode, 2 servers operate in a failover relationship where an active server is responsible for leasing IP addresses and configuration information to all clients in a scope or subnet, while a secondary server assumes this responsibility if the primary server becomes unavailable. A server is primary or secondary in the context of a subnet.
In a load balance mode deployment, which is the default mode of operation, the two servers simultaneously serve IP addresses and options to clients on a given subnet. The client requests are load balanced and shared between the two servers.
Auto State Switchover Interval : A server that loses communication with a partner server transitions into a communication interrupted state. The loss of communication may be due to a network outage or the partner server may have gone offline. Since there is no way for the server to detect the reason for loss of communication with its partner, the server will continue to remain in communication interrupted state until the administrator manually changes the state to partner down. Alternatively, DHCP failover has a provision for automatic transition to partner down state based on a time out interval. This is a configurable element called the auto state switchover interval. The default value for auto state switchover interval is 10 minutes.
Enable Message Authentication : To configure message authentication, the DHCP failover setup wizard prompts the administrator to provide a shared secret. As part of the failover relationship creation, the failover setup wizard provisions the shared secret for message authentication to each of the servers in the failover relationship.
6 – Next, confirm the settings and click Finish.
7 – Now log in to both of the DHCP Server (in my demo OSI-ADDS01 and OSI-SVR01, which both Server hosted my DHCP). Confirm that both DHCP Services is running and you can have both Server having same settings.
8 – Next, log in to your client PC, in my demo i have Windows 8.1 machine and now open CMD and type ipconfig /all to get IP information.
— Confirm that your client machine is receiving IP from DHCP Server. in my demo the IP is coming from my OSI-SVR01 server (172.16.0.103)
— to test the DHCP Failover, disconnect the network on the 1 of the DHCP Server (in my demo it OSI-SVR01 server)
9 – now, release and renew the IP from your client machine (ipconfig /release.. ipconfig /renew).. please refer to pic..
10 – confirm that you now receive IP from another DHCP Server (in my demo its ADDS01 server with IP 172.16.0.101).
— So it prove that our DHCP Failover is working…
12 – now back to OSI-ADDS01 Server, right click DHCP scope, select “Properties“.. click Failover tab, and you can verify Failover status stated that “Lost contact with Partner”..