Hi, I read that Outlook client connects with CAS on the NSPI endpoints. I need to know (What happens next) Does the CAS server reffer the outlook client to Global Catalog server because NSPI interface is only present in Global Catalog server. Please guide me.

Yes that's correct for Exchange 2007, Exchange will refer the client to the GC NSPI endpoint. For 2010 clients connect directly to the CAS array for the NSPI endpoint and not the GC.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Hi James, I understand clients will connect to CAS for NSPI Endpoint. After client connects to NSPI endpoints on CAS, then for active directory search what will they do? Will they not contact GlobalCatalog server? I am asking this because I had read that NSPI interface exists only on Global Catalog. Please guide Thanks!

The clients do not connect to the CAS NSPI endpoing, the CAS just refers the client to the GC's NSPI endpoint permanently, so all directory lookups will be performend against the GC by the client. James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

HI James. So is this for Exchange 2010 that " The clients do not connect to the CAS NSPI endpoing, the CAS just refers the client to the GC's NSPI endpoint permanently, so all directory lookups will be performend against the GC by the client." Thanks!

That is for 2007, for 2010 outlook clients connect directly to the CAS NSPI endpoint which services the directory requests using the new address book service.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Hi James, I hope I am not boring you with my questions. Just one last question James. Does the 2008r2 global catalog server have NSPI interface? If yes, then what is it used for.

Yes once it's enabled as a GC an nspi endpoint is binded to the server. The nspi endpoint exists but doesn't mean it will be used by clients unless you are using legacy Exchange severs and outlook clients. For 2010 the cas has the nspi endpoint and once the outlook clients to the cas, the address book service on the cas proxies any AD requests to the GC on behalf on the client using active directory driver. "The Active Directory Driver is the core Microsoft Exchange component that allows Exchange services to create, modify, delete, and query for Active Directory data."James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Thanks James. Thanks a lot buddy