Skype for Business Mobile Internal discovery address: /Autodiscover/AutodiscoverService.svc/root Lync 2010/2013 Mobile Internal discovery address: /Autodiscover/AutodiscoverService.svc/rootĮxternal discovery address: /Autodiscover/AutodiscoverService.svc/root Skype for Business Desktop Internal server name: :443 Lync 2010/2013 Desktop Internal server name: :443Įxternal server name: :443 When you’re in a Hybrid scenario and you want to bypass the on-premises automatic sign-in process (reasons are myriad why you would potentially need to do this – a separate discussion for another time), you can hard-code the server discovery address for both the Lync desktop clients and the Lync mobility clients: Lync 2013 DNS Requirements for Autodiscover Lync 2010 DNS Requirements for Automatic Client Sign-In Office Communicator Sign-In and Discovery If you’re looking for information on how that works, I would suggest starting here: If the clients were not hard-coded to utilize a certain server FQDN, the UC clients would begin an automatic server discovery process to auto-magically find where it should attempt to register. Since the days of OCS there has been a method to manually configure Microsoft’s UC clients with a specific server address for internal & external sign-in capabilities.