Assign the Team Foundation Server URL that will be used by lab managed build agents to connect to Team Foundation Server. ...

Assign the Team Foundation Server URL that will be used by lab managed build 
agents to connect to Team Foundation Server. 

    TfsConfig lab /settings /collectionName:
                      [/labUrl:]
                      [/noprompt]]
                      [/list]
   
    Use the following options with the /settings option:
        /labUrl:
            Optional. Specifies the Team Foundation Server URL that will 
            be used by build agents which are auto-configured by Lab 
            Management. We recommend you use the fully-qualified domain name 
            (FQDN) in this URL to avoid communication problems when the 
            virtual machine is not on the same domain as the server running 
            Team Foundation Server. The default value for this is equal to 
            the 'NotificationUrl' converted to a FQDN format. 

        To restore the default value for labUrl from the command line, specify 
        an empty value for labUrl. To override the labUrl for any team project 
        collection, specify the collectionName parameter.