Just can't get enough of IT

Problem

The Skype for Business client merges contact data from different sources when displaying the contact card. The merged data is used to perform name resolution when performing a user search. In a more complex deployment scenario where an email domain name is in shared use in two in Active Directory forests you might run into a situation where the Skype for Business client tries to use the wrong target address.

Such a scenario would look like as follows.

Forest A is used as a dedicated infrastructure for developers. When logged on to the development network the users should be able to skype with colleagues currently connected to the default office client network.

Forest B is the default office client network.

Clients logged on to forest A connect to the Skype for Business infrastructure in forest B as external clients. Forest A is used for user account authentication while forest B is used for Skype for Business connection and authentication. 

Forest A

Forest A runs an Exchange Server 2013 organization.

• Active Directory domain: SednaDevelopers.com
• SMTP domains: dev.Sedna-Ltd.com, Sedna-Ltd.com

Forest B

Forest B runs an Exchange Server 2013 organization and a full Skype for Business 2015 server deployment.

• Active Directory domains:
  • root.internal - Forest root, resource domain with Skype for Business 2015, Exchange 2013
  • Sedna-ltd.com - user domain, primary email domain
• SMTP domain: Sedna-Ltd.com

Both Active Directory forests to not have trust of any sort established.

Such a configuration would result in forest A users trying to contact a Skype for Business user using the wrong address. Instead of using John.Doe@Sedna-Ltd.com the Skype for Business client of Jane Doe@Sedna-Ltd.com (logged on to forest A) would try to contact John.Doe@dev.Sedna-Ltd.com. As there is no endpoint defined for dev.Sedna-Ltd.com a connection could not be established. Therefore, no availability information is available and no call or chat connection could be established.

Reason

The Skype for Business client uses merged data pulled from the Skype for Business address and from the local (Forest A) Active Directory (GAL). This results in a connection attempt to John.Doe@dev.Sedna-Ltd.com.

Forest A object attributes

• proxyAddresses: SMTP:John.Doe@dev.Sedna-Ltd.com
• proxyAddresses: smtp:John.Doe@Sedna-Ltd.com
• msExchShadowProxyAddresses: sip:John.Doe@Sedna-Ltd.com
• msExchShadowProxyAddresses: SMTP:John.Doe@dev.Sedna-Ltd.com
• msExchShadowProxyAddresses: smtp:John.Doe@Sedna-Ltd.com
• msRTCSIP-UserEnabled: TRUE
• msRTCSIP-PrimaryUserAddress: John.Doe@Sedna-Ltd.com

Forest B object attributes

• proxyAddresses: sip:John.Doe@Sedna-Ltd.com
• proxyAddresses: SMTP:John.Doe@Sedna-Ltd.com
• msRTCSP-InternetAccessEnabled: TRUE
• msRTCSIP-UserEnabled: TRUE
• msRTCSIP-PrimaryUserAddress: John.Doe@Sedna-Ltd.com

Solution

• Create a new text file named ocapi_test.config.xml using notepad
• Add the following Xml text

<?xml version="1.0"?> 
<settings> 
  <UseMsoSearch>false</UseMsoSearch> 
</settings>

• Save the file in same directory as Lync.exe
• Terminate the Skype for Business client
• Delete all files from the users SIP folder
  • e.g. C:\Users\JDOE\AppData\Local\Microsoft\Office\16.0\Lync\sip_Jane.Doe@Sedna-Ltd.com
• Restart the Skype for Business client

Enjoy Skype for Business