I am already sure this is a really dumb question, but I have to ask. Today I had to reboot one of our domain controllers. It happened to be the one that Exchange is configured to use. I was not expecting all the clients to lose their connections to the Exchange server. Everyone was getting an authentication popup. Even after the domain controller came back up users had to close Outlook and reopen in order to connect. Prior to migrating to Exchange 2007 (from E2003) I was able to reboot a DC any time I wanted to an not have any reprecussions. My question is what happened today, is that normal or as the preffered MS response, this is by design? Is there a best practice I should follow? A way to prevent this from happening, other than not rebooting that server?

Hi, Please run Get-ExchangeServer | Format-List from Exchange Management Shell to check whether you have specify certain domain controller. Note: Please pay attention to the below parameter: StaticDomainController StaticConfigDomainController StaticGlobalCatalogs If yes, then if you modify any server or organization configuration it will use the domain controller to read and write to the ActiveDirectorydirectory services. So please avoid to shut down this only domain controller. Besides, you can check organization configuration. If you need to restart this DC frequently, then I recommend you to change the statics domain controller or just let this configuration blank. Note: To modify this setting so that no single domain controller is set to perform all server and organization configuration changes, clear the Configuration Domain Controller check box, and then click OK. If this check box is cleared, the domain controller used to perform configuration changes will be the domain controller to which the computer is currently connected. To view the domain controller to which a computer is currently connected, use the netstat command from a Command Prompt window and search for LDAP in the Protocol column. For more information about netstat, see Netstat in the Microsoft Windows Server TechCenter. Related information share with you: Organization Configuration > Configuration Domain Controller http://technet.microsoft.com/en-us/library/aa998227(EXCHG.80).aspx Get-ExchangeServer http://technet.microsoft.com/en-us/library/bb123873(EXCHG.80).aspx Set-ExchangeServer http://technet.microsoft.com/en-us/library/bb123716(EXCHG.80).aspx Hope it helps. Xiu