I'm confused on the issue of DC/GC placement within a multi site Exchange org. The Exchange 2007 system requirements clearly states: In each Active Directory site where you plan to install Exchange 2007, you must have at least one domain controller that is also a global catalog server and is running Windows Server 2003 SP1 or a later version. However, Exchange will use an out of site DC if the local DC is unavailable. That being the case, is there or is there not a requirement to have a DC in each AD site that has and Exchange server? Is the requirement, as stated above, only apply to the initial installation of Exchange? Other than possible perfomance issues, what's the risk of not having a local DC? It would save us money if we didn't need so many additional servers. Ted

Local GC is always recommended for Exchange. It could use a GC across site, but performance will degrade and you will hear a lot of complaints from your users as well as the WAN link utilization will go up. This is general answer, but the specific answer depends on how many users, what version of outlook, cached mode or not, wan link speed.

Agree with LMurthy. there should have to be DC and GC. My question is why wouldn't you have? Why would you create issues to WAN Link between the site by not having DC and GC on the site. There will be performance issue on the Exchange Server users will see Latency and end of the day it will make them frustrated. Cheers, Gulab | MCTS-MCITP Messaging: 2010 | MCTS-MCITP Messaging: 2007 | MCC 2011 | Skype: Gulab.Mallah | Blog: www.ExchangeRanger.blogspot.com

I agree with both Gulab and LMurthy, and for adding some idea.. If it's a small site and customer and have a tight budget to follow, you make can place a Hyper-V or VMware server at that site with a lot of memory and disk and then run the DC on one VM and Exchange on another.. Just a suggestion.. :)Jonas Andersson | Microsoft Community Contributor Award 2011 | MCITP: EMA 2007/2010 | Blog: http://www.testlabs.se/blog | Follow me on twitter: jonand82

Hi, Jonas's idea is pertty good. The risk of putting DC and GC on another side is that when there is a netwook problem between two sides your exchange server will down because it cannot find DC available. Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.