Setting ExternalURL for Outlook Anywhere clients

There is a parameter known as the ExternalUrl parameter. The Outlook Anywhere client needs to connect to various services such as Exchange Web Services, Offline Address Book and also Unified Messaging. The Exchange Web Services provide functionality such as the Out of Office message. To connect to these services, the Outlook Anywhere client first locates the autodiscover service.  An example  is https://autodiscover.YourDomainName.com/autodiscover/autodiscover.xml. You can set the URL’s in this file by using the following cmdlets. 
Set-WebServicesVirtualDirectory –Identity ‘CAS1EWS (Default Web Site)’ –ExternalUrl https://autodiscover.YourDomainName.com/ews/exchange.asmx
Set-OabVirtualDirectory –Identity ‘HUBCAS1EWS (Default Web Site)’ –ExternalUrl https://autodiscover.YourDomainName.com/oab
Set-UmVirtualDirectory –Identity ‘HUBCAS1EWS (Default Web Site)’ –ExternalUrl https://autodiscover.YourDomainName.com/unifiedmessaging/service.asmx