Configure Client access server – load balancer the traffic between the CAS servers

Today we will look at load balance the traffic between the client access servers. So we have 2 CAS server.

We will use Windows Network Load Balancing. Windows Network Load Balancing is a common software load balancer used for Exchange servers. There are several limitations associated with deploying WNLB with Microsoft Exchange.

  • WNLB can’t be used on Exchange servers where mailbox DAGs are also being used because WNLB is incompatible with Windows failover clustering. If you’re using an Exchange 2013 DAG and you want to use WNLB, you need to have the Client Access server role and the Mailbox server role running on separate servers.
  • WNLB doesn’t detect service outages. WNLB only detects server outages by IP address.

So let us start.

So we need to networks: One for client connectivity another one is for NLB:



After that, we need to install WNLB. To do that follow steps below:


Select the feature and click Next and finish the installation:


After WNLB installed we can add host.


To do that click New Cluster:


And then type CAS server host name and click Connect, Select NLB network, Click Next:


Click Next:


Type cluster IP address and click OK.


Then type IP address and full internet name of the cluster, Click Next:


Click Finish:


So 1st CAS server added.


Same way you can add another CAS server:



Do not forget to add mail.tekbloq.local DNS records to DNS server.


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