HI, I've some confusion regarding Global Catalog servers of large Exchange environments. If we think of a scenario like this; 3 Active directory sites- Site A, Site B, Site C Site A contain 1 CAS, 1 HUB and 4mailbox servers Site B contain 1 CAS, and 5 mailbox servers Site C contain 1 CAS server and 10 mailbox servers. HUB server in Site A responsible for all incoming messages and send messages.CAS server in Site A is a internet facing CAS server and that server will do Proxying for all other CAS servers. How to place Global catalog servers in each site? Regards Dilina A.

Hi, Microsoft Best practice is 1 global catalog server must place in each active directory site where mailbox server installed. And every 4 mailbox servers require 1 Global catalog server. (1:4).if you have 8 mailbox servers in the site you need to configure 2 Global Catalog servers. For your situation I would like to suggest below GC placement. 1 Global catalog server for Site A, 1 global catalog server for site B(use high-end server than other GCs) 2 global catalog servers for Site C ResourcesEstablishing a Proper Global Catalog Placement Strategy Exchange 2007 System Requirements Best Practices for Transitioning an Exchange Organization RegardsChinthaka

Hi, You can find some more details on placing GC in the below mentioned linkhttp://www.msexchange.org/articles-tutorials/exchange-server-2007/planning-architecture/exchange-2007-sizing-cheat-sheet.html Regards,Krishnahttp://smtpport25.wordpress.com/