Sunday, August 16, 2015

OWA-IM Integration with Exchange 2010 CAS Array


Instant messaging integration to Outlook Web Access is a great feature for Exchange 2010 OWA where users can chat with there peers. Introduced in Exchange 2007, this feature is improved a lot. Now you do not need to configure or modify IIS to get OWA-IM working. Instead all the configuration in on exchange is being done at OWA virtual directory level.

Configuring exchange server information at Office Communication Server is different compared to Lync 2010 server. We will have to create 'TrustedApplicationPool' to represent exchange for any sip communication because exchange is non-SIP based server for Lync server.

Configuration of single server is quite simple compared configuring OWA-IM integration for client access array because of HLB/NLB ( read Hardware load balancer and Software load balancer).

Steps to configure OWA for IM integration

Configure Cas array to Exchange 2010 sp1 Cas servers.

Once Exchange 2010 CAS has been installed and configured. Install and configure Windows NLB from windows features on all the CAS servers which will be part of NLB configuration.

After configuration your NLB should show all the nodes as converged.

Windows NLB showing all available nodes.

In my scenario, I have configured "mail.uc-tech.com" as the virtual identity of the NLB which resolves We need to create an 'A' record for mail.uc-tech.com.

Run following command to configure CAS array from any of the CAS server.

New-ClientAccessArray -fqdn 'mail.uc-tech.com" -Name "CAS Array" -Site "Default-First-Site-Name"

Configuring new CAS array using Power Shell

You must configure CAS array for your mailbox database, I ran the following command

 Set-Mailbox Database "Mailbox Database 0829338392" -RpcClientAccessServer "mail.uc-tech.com" -Confirm

Create a new user mailbox and enable user for sip.

Create new user mailbox and enable the user for sip

Enable user for Sip

 The power shell command to enable the user is run from Lync server 2010, not from exchange server 2010.

Configuring Exchange Server for Instant Messaging


Download CWAOWASSPMain from Microsoft, install it on all the servers in the CAS array. This will not install any software on the servers but you will find a new 'Directory' in C:\ drive which will have all the software for installation.

Download CWAOWASSPMain

Complete installation of these in ascending order on all the CAS servers.

Extract CWAOWASSPMain and ready for installation

To verify that your installation is successful, open regedit and browse to 
HKLM/System/CurrentControlSet/Services/MsExchange OWA/Instant Messaging

Registry for Instant Messaging pointing to Microsoft Rtc.UCWeb.dll

Verify that the Microsoft.Rtc.UCWeb.dll is existing and if not then we need to run setup again.

Configuring OWA virtual directory for Instant Messaging


When users log on to OWA, Instant Messaging need to initiate at the same time. This is only possible if  OWA contact the Lync 2010 pool and get presence information for user. Since, user is already sip enabled, this won't be difficult.

However, OWA virtual directory must be aware of sip server for communication.

First we create a Certificate for CAS array. Create a certificate request from Exchange Management Console, you can also submit you request an Enterprise CA or a public CA to get the certificate.

But consider few important points,

  1. Root certificate must be installed on CAS server and same certificate must be installed on all the CAS servers.
  2. 'Subject Name' of the certificate must point to fqdn of the CAS array.
  3. There is not need to assign this certificate to any service. But it must be imported to the local Certificate Store.

Set-OwaVirtualDirectory -InstantMessagingType Ocs -InstantMessagingServer FE.uc-tech.com -InstantMessagingCertificateThumbprint -Identity "CAS/Owa (Default Web Site)"

Set Instant Messaging type, IM Server name and certificate details on OWA virtual directory

Instant messaging server here is Lync 2010 standard front-end server. Thumbprint of certificate is from the certificate is from the certificate that you create for CAS array. Run the above command on all CAS servers with identity reflecting respective CAS servers, where you want to run the command.

Enable IM messaging on OwaMailboxPolicy

Run Set-OwaMailboxPolicy -InstantMessagingEnabled:$true -InstantMessagingType Ocs -Identity Default

Finally, verify all of your configuration by running Get-OwaVirtualDirectory | fl in*

Get-OwaVirtualDirectory results

Configuring Lync Server for OWA-IM integration


Now that we have configured Exchange 2010 server for OWA-IM integration.Since, Exchange server is not a SIP server, we need to create a TrustedApplicationPool and Trusted Application in Lync topology which will represent Exchange CAS array.

  1. Create a TrustedApplicationPool 
Create a TrustedApplicationPool

 Select the 'Multiple Computer pool' which represents your CAS array.

Select Multiple Computer Pool and Next Hop

Expand the TrustedApplicationPool and your can see all the CAS servers within the array.

        2. Create Trusted Application for Lync 2010 server

Run New-Trusted Application command to do that

Run New-Trusted Application

Run Enable-Cs Topology command.

Enable Topology

Testing  OWA-IM integration

To verify the OWA-IM configuration, log on to Outlook Web App.

Log on to OWA

Check the Contact List for other SIP enabled users



OWA-IM  is very easy to configure and very useful feature for exchange users because it gives a common platform to use two methods of communication and provides presence information to others through IM integration.
Most of the time you may not get it configured first time, Certificate related problems are common. 
If your having issues with communication between Exchange and Lync or vice-versa, then analyse SIP trace on Lync server and IIS logs in Exchange. You should also look for windows event viewer for possible errors. Those are good place to start working on issues related to OWA-IM.

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