Hi All In Exchange 2003, from memory, the System Attendant (SA) was responsible for a lot of stuff, including all the AD discovery, communication, DSAccess stuff etc. In Exchange 2007, there is the System Attendant *and* AD Topology Service. And, if I look at their PID's in Netstat, both seem to connect to GC/DC's. Could someone clarify for me? Which one does Exchange use for AD connectivity? This article: http://www.msexchange.org/articles-tutorials/exchange-server-2007/planning-architecture/how-exchange-server-2007-core-services-work-together.html Says that both the SA and Topology Service connect to AD to provide Exchange with DC, but it's a bit confusing. Thanks in advance

Here is a good article to explain the brief function of the services in Exchange 2007: http://technet.microsoft.com/en-us/library/aa998342(EXCHG.80).aspx Thanks, Simon