We have ArcGIS Server 10.1 with Windows Domain as Identity Store, and ArcGIS Server Roles as role store. Now I need to figure out when each of our 100+ users has last authenticated. We are using GIS Tier authentication, 2 virtual machines running ArcGIS Server, no ArcGIS Web Adaptor, one CISCO load balancer. Any ideas if this information can be queried somewhere? Thanks!