Hi Everyone: Environment: 3 Root Domains 3 Child Domains 3 Exchange 2007 Servers (Stores, Client Access, Transport) Currently, we have 3 domain controllers all with the global catalog role. FSMO roles are on DC01. DC02 and DC03 are secondary. When we shut down DC02, some (not all) clients are unable to process emails. All others are unaffected. On Exchange Management Console, in "Organizational Configuration\Modify Configuration Domain Controller\", nothing is listed or checked. In "Client Access\Properties\System Settings", all our root and child domain controllers are listed. Can someone tell me why some of the clients are unable to process email when a secondary DC is taken offline? Thanks

What kind of clients are these?

On Wed, 10 Aug 2011 22:19:32 +0000, Steinomite wrote: > > >Hi Everyone: > >Environment: 3 Root Domains 3 Child Domains 3 Exchange 2007 Servers (Stores, Client Access, Transport) > >Currently, we have 3 domain controllers all with the global catalog role. FSMO roles are on DC01. DC02 and DC03 are secondary. When we shut down DC02, some (not all) clients are unable to process emails. All others are unaffected. > >On Exchange Management Console, in "Organizational Configuration\Modify Configuration Domain Controller\", nothing is listed or checked. In "Client Access\Properties\System Settings", all our root and child domain controllers are listed. > >Can someone tell me why some of the clients are unable to process email when a secondary DC is taken offline? There aren't any "secondary" DCs. All DCs are peers. What happens if those clients simply exit and restart Outlook? They were probably using the GC in the machine you shut down. They may even correct the problem by themselvers after 15 minutes, or so. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

are they located on single site or multiple sites?Abhi

Hi Steinomite, Any update for your issue, please post more information, and we could do more research regarding to your issue. How about restart the the issue outlook clients. Any application event log on the exchange 2010 server? If no, the client end could work well after the restarting or wait for a period time. Regards! Gavin TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com 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.

Thanks for the quick response. Thanks for correcting me Rich! 1. Clients are Dell workstations running Windows XP and Outlook 2002. 2. Multiple sites, but the users affected were both in our primary site. 3. One user rebooted and the other user did nothing. The first user seems to remember that a reboot fixed it and the second user said it started working after that DC was turned back on. 4. I checked the system and application logs on both servers and there was nothing relevant. So if I understand this correctly, each client connects to exchange through a different DC and when that DC goes offline, it needs to authenticate against a different DC? How can I make it so that all clients connect to the same DC? Thanks

Thanks for the quick response. Thanks for correcting me Rich! 1. Clients are Dell workstations running Windows XP and Outlook 2002. 2. Multiple sites, but the users affected were both in our primary site. 3. One user rebooted and the other user did nothing. The first user seems to remember that a reboot fixed it and the second user said it started working after that DC was turned back on. 4. I checked the system and application logs on both servers and there was nothing relevant. So if I understand this correctly, each client connects to exchange through a different DC and when that DC goes offline, it needs to authenticate against a different DC? How can I make it so that all clients connect to the same DC? Thanks One issue is the client version. Its the not most robust for handling GC failures and it out of support. ( Office XP that is) Here is the article on how to statically set a GC for Outlook. But I wouldnt do that. Bad idea. What if the GC you hardcode is down? http://support.microsoft.com/kb/319206 How to configure Outlook to a specific global catalog server or to the closest global catalog server

We are moving to Office 2010 this fall. How does 2010 handle GC failures differently than XP? And thanks for the link. But I think your right, it's not wise to put all your eggs in one basket. Thanks

We are moving to Office 2010 this fall. How does 2010 handle GC failures differently than XP? And thanks for the link. But I think your right, it's not wise to put all your eggs in one basket. Thanks Well, heres the thing, Outlook 2002 was the first version out of the box that refreshed its GC referral whenever Outlook is started or a GC failed (Outlook 2000 didnt do that till a later service pack). Now having said that, Outlook 2000/2002 and 2003 were never that good from my own personal experience in handling GCs failures regardless. Note that the Exchange server has a role in this as well. The dsproxy GC referral process relies on dsacess to provide it a list of working DCs. So I havent really given you a great answer, but Outlook 2007/2010 are much better at handling referrals on the fly ( and cache mode should be deployed as well). In fact, I can safely say that since Exchange/Outlook 2007, I cant recall Outlook ever noticing when a DC was removed, shutdown or was plain just inaccessible ( those soft errors)

Thanks Andy for all your help (and the others)

What you can try is to disable dsproxy on Exchange server. http://technet.microsoft.com/en-us/library/aa998409(EXCHG.80).aspx Exchange server will behaves like a proxy for Outlook clients instead of referring the clients to the appropriate global catalog server for direct communication. If you have some extra CPU cycles on Exchange to spare this might be a good thing. lasse at humandata dot se, http://anewmessagehasarrived.blogspot.com