Hi I had some questions on Exchange 2007 and Active Directory that I was hoping someone could help with. I have listed them in order so they can be answered seperately. 1. Does Exchange only use one GC or DC at a time, even though many are listed in the Exchange Management Console properties of a mailbox server? Is it one GC and one DC, or one GC or one DC? 2. How can I find out specifically which GC/DC Exchange is using? Is Event ID 2080 the only way, there is no Powershell command that will instantly tell me? 3. If we are having DC/GC problems, how can I find out if Exchange is affected? Is there a command I can run on Exchange that tells me whether it has succesfully connected to a DC/GC, and that server is servicing LDAP/GC requests ok? 4. If the AD Topology service won't start, what's the best way to troubleshoot this? 5. I assume there is no way to get Exchange to use a different DC/GC apart from changing this value in the registry? For instance, we had an issue today where the NIC of a GC was playing up. We have a couple of Exchange servers in the same AD site as this GC and I wanted to make them use another one, even though the GC was dual NIC'd and there were no problems as such.

Quite some questions, which could qualify for a l o n g answer. Here's the short version: (1) Exchange does load balance its requests. Guidance on Active Directory design for Exchange Server 2007 http://msexchangeteam.com/archive/2007/03/28/437313.aspx (2) Event ID 2080 reports on all DCs the MS Exchange Topology service finds, not on what Exchange actually uses. You can issue this command for that: Get-ExchangeServer -Identity <server name> -Status | fl. This will provide the information you're after. http://technet.microsoft.com/en-us/library/bb123873(EXCHG.140).aspx (Exchange 2010, but should suite your needs) (3) Guess Exchange Best Practices Analyzer (ExBPA) will help you in that case and Test-SystemHealth. (4) I would start with the event logs, ExBPA and perhaps use Dcdiag http://technet.microsoft.com/en-us/library/cc758753(WS.10).aspx (5) Set-ExchangeServer. Set-ExchangeServer cmdlet can ease domain controller workloads http://searchexchange.techtarget.com/tutorial/Set-ExchangeServer-cmdlet-can-ease-domain-controller-workloads MCTS: Messaging | MCSE: S+M

Great answers! > Exchange does load balance its requests. So Exchange actually uses a combination of DC/GC's at the same time? Doesn't lock onto one specifically? Or does it use one for, say, 1 hour, then another for another 1 hour? > Guess Exchange Best Practices Analyzer (ExBPA) will help you in that case and Test-SystemHealth. Can I run Test-SystemHealth on a prod mail server during working hours?

Basically Exchange tries to perform an evenly distributed load-balancing on a round robin basis. It's actually a bit more complicated. While the documentation below is for Exchange 2003, my understanding is that this still holds true for Exchange 2007. LDAP Connection Load Balancing and Failover http://technet.microsoft.com/en-us/library/aa996247(EXCHG.65).aspx#LDAPConnectionLoadBalancingAnd I would be very careful with potential resource-hungry processes during work hours. Now, I have become obsessed with SCOM 2007 R2 -- very hard not to become completely addicted once you have come to some grips with it -- and here are the considerations the developers of the management pack for Exchange 2007 have made. Determine the Best Time to Run Resource-Intensive Rules and Monitors http://technet.microsoft.com/en-us/library/dd772551.aspx Configuring the Native Exchange 2007 MP for OpsMgr 2007 R2 (Part 5) http://www.msexchange.org/articles_tutorials/exchange-server-2007/management-administration/configuring-native-exchange-2007-mpopsmgr-2007-r2-part5.htmlMCTS: Messaging | MCSE: S+M

> Event ID 2080 reports on all DCs the MS Exchange Topology service finds, not on what Exchange actually uses. You can issue this command for that: Get-ExchangeServer -Identity <server name> -Status | fl. This will provide the information you're after. Thanks, I get a list of CurrentDomainControllers, CurrentGlobalCatalogs, and also the CurrentConfigDomainController. Would I be correct that the first two are the ones that Exchange has 'discovered', but may not necessarily using...and the last is the one that Exchange uses? In which case, is that a DC or GC, and what's it using it for? Reading or writing? Also, I guess I can use something like NLTEST /DSGETDC, but this is a Windows OS command, not Exchange. So, although the OS maybe finding a DC/GC fine, doesn't prove that Exchange can? Or is this not possible? Finally, I was returned dc1.domain.com as the CurrentConfigDomainController. I ran DCDIAG /S:dc1.domain.com...it failed some of the tests (perhaps because I don't have access rights on the DC), do you know which tests need to pass to show that Exchange-DC connectivity is working fine? Is it just the initial "Connectivity" test?

Hi, The Working DC, Working GC and Configuration DC are different. The Working DC are seldom utilised as they can only provide information about objects in the domains in which they are located, it's only used if Exchange has sufficient knowledge that the recipient object it's looking for is in a certain domain. For the Working GC, the GC is used when opening the address book, hitting Ctrl+K, double clicking a recipient on a message. The Configuration DC is provided as the reference point for AD configuration information. DSAcces--60% (65% to Working GCs, 30% to ConfigDC, 5% to Working DCs) Categorizer--30% (100% to Working GCs) DSProxy--10% (100% to Working GCs) Thanks Allen Allen Song