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Monthly Archives: November 2013

In my series of building a Lync Server 2013 High Availability environment, we have in the last three parts been setting up Load Balancing for the internal Lync Servers.

In Part 14 we have setup the Kemp Load Balancers that is uses internally

In Part 15 we have setup Load Balancing of the Office Web Apps Servers

In Part 16 we have setup a combination of DNS Load Balancing for the Lync Services and Hardware Load Balancing for the Web Services.


In this part we will look on how to setup the other alternative to the load balancing method in part 16, which is Load Balancing of all the Lync Services.

When using this method you must be sure that the Load Balancers can handle all the load of all the Lync Services.

Let’s first have a look at the topology builder, which you should configure like this: →']);" class="more-link">Continue reading

In the last two posts (part 14 and part 15) we have been setting up Kemp load balancers for our internal Lync servers. We will now continue with this setup, and load balance the frontend servers.


As I started with in Part 14 you can load balance the frontend servers in two ways.

  1. DNS Load Balancing and Hardware Load Balancing the Web Services
  2. Hardware Load Balancing all Lync Services

This post is the first part where we uses both DNS load Balancing for the native Lync services (like sip) and the hardware load balancer for the web services in Lync.

First we need to change to topology so that the internal web services uses another name that the pool name – in this case cswebint.exchangepro.local

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I the last post we installed and configured the internal kemp load balancers. In this post we will be setting up load balancing for the Office Web Apps servers


The Lync HA setup contains two Office Web Apps Servers.


Start by exporting the WAC server certificate from one of the WAC servers. The certificate should contain the WAC farm name (both internal and external), and the two server names.

Navigate to Certificates -> SSL Certificates and click Import certificate.

→']);" class="more-link">Continue reading

In the last post, we installed two additional frontend servers to the Lync High Availability environment that we has been creating for quite some time now.

In part 7  when we installed the first frontend server, we made the configuration on the Frontend pool dns records, so that the pointed to the first frontend server, which we had at that time. We did the same for the Office Web Servers and Directors servers.


Lets start by talking a little bit about how to load balance Lync.

Both the Lync clients and Lync Servers can be using DNS Load Balancing. This is achieved by configuring multiple records in DNS to point to the same name.

When the clients and servers query DNS for a records – it gets all results for a record returned – so if three records points to the same name, the result will include these three records.

The client and server will then contact the first server and if no response is received, it will contact the next.

The Lync servers will load balance the clients automatically between the available servers though an algorithm, which also will redirect clients to the other servers in the pool.

But there is a catch – DNS load balancing only works for Lync traffic like the sip traffic (5061/TCP), it doesn’t work for web traffic like https (443/tcp), and that is why you need a load balancer for the web traffic. →']);" class="more-link">Continue reading

Exchange Server 2013 CU3 has been released and contains fixes for several critical problems in Exchange 2013, and Microsoft recommends it to all customers.

As with the other Exchange 2013 updates this version is a complete installation, so on new installation of Exchaneg 2013, you don’t need to install the RTM or any other versions first.

Have a look at the Exchange Team blog for importen information about this update

Get the update here

Windows Server 2012 R2 contains a new feature called Web Application Proxy. WAP is a very simple reverse proxy which can be used to publish the Simple URLs in Lync Server 2013.

In this post, I will guide you through how to setup and use it as a reverse proxy for Lync and the Office Web Apps Server.


I have in my setup defined these public DNS names:

  • Csweb.exchangepro.dk (Frontend Server external name)
  • Cswebapp.exchangepro.dk (Office Web App External name)
  • Cswebdir.exchangepro.dk (Director Server external name)
  • Lyncdiscover.exchangepro.dk (Lync Discover url) →']);" class="more-link">Continue reading

In my Lync Server 2013 High Availability environment series, we have now deployed most of our Lync servers, but we still need to deploy two more frontend servers.


The topology that we have deployed so fare consist of an Enterprise Pool with one frontend server.

The minimum recommend number of frontend servers in an Enterprise Pool is three – Have a look at this Microsoft page for guidelines about planning for frontend servers: http://technet.microsoft.com/en-us/library/gg412996(v=ocs.15).aspx


At this point I assume that you have installed the two new frontend servers with the same specification has the first server (see part 5: http://exchangepro.dk/2013/09/19/prepare-your-servers-for-lync-server-2013-ha-part-5/).

Before you start I will recommend that you do this in maintenance window, because you will need to reboot the frontend servers, which can cause disruption for the users.

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The new November update for the Lync 2013 client has been released which contains some new features:


The first thing you will notice is that the profile pictures is in lined in chat communications, like you have it on Lync Mobile:

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We have now come to the part where we are going to deploy the reverse proxy servers. Because we are deploying a high availability Lync environment, the reverse proxy servers should of course also be redundant.

In my redundant reverse proxy setup, I will use two virtual hardware load balancer from Kemp Technologies in an active/passive setup.

I will deploy two VLM’s, which is going to be placed in the DMZ Internal zone.

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