Hi We have a multi-domain forest; uk.kam.com, usa.kam.com and japan.kam.com One Exchange org. Mainly Exchange 2003 but some new Exchange 2007 servers we are testing (all roles have been deployed). My mailbox is on exch1.uk.kam.com, which is an Exchange 2003 mailbox server. If I go to my Outlook 2007 client, and then CTRL-click the Outlook icon, I can see the MS Exchange Connection Status. There are entries for Mail, Directory and Public Folders. Strangely, there are multiple DC's for Directory (all in my AD site however), and multiple servers for Mail (this includes mailbox servers in the UK and USA!). Does anyone know why this is? I presume it's actually by design and there is nothing wrong, however I was under the impression that Outlook was given a specific DC to use via the DSProxy process, and that the only MAPI connection would be to the Exchange server my mailbox was located on. The reason I noticed this was because an Exchange 2007 server in the US was rebooted earlier. Technically, this had no users on it so shouldn't have impacted, but my connection to Exchange was terminated and I was prompted for my credentials again. I assume that this US Exchange server was one of my "Mail" servers, hence the reason I had to restart Outlook to get connectivity? I am in cached Exchange mode if that makes a difference.

Multiple DCs is normal as is multiple mailbox servers ( If you have opened a shared calendar on another mailbox server for example, it will show the mailbox server in the connection status).

Hi AndySo how would Outlook choose multiple DC's? Surely the DSProxy service only returns one DC - how would it know about any others? Or does DSProxy actually provide more than one DC to refer to?As regards the multiple mailboxes - yep, I do have some shared mailboxes, that explains it. So, would I be correct in thinking that when Outlook first connects with to my primary mailbox, Exchange provides details on the mailbox servers for the shared mailbox servers I have, or do these shared mailboxes all attempt to speak to Exchange directly themselves in the same way my primary mailbox does?

Outlook doesnt choose them, its whatever DC the dsproxy service refers Outlook to. ( round-Robin among eligible GCs) Now when I say multiple DCs, I mean the same DC listed more than once. ( You can have the same mailbox server listed more than once as well). I've seen it listed 7 times or more on startup. A lot of that depends on client mode, add-ins, what the client is going etc... If you click the reconnect button in the status dialog box, you can see it grab another DC is its deemed eligible by the dsproxy service.More Info:http://msexchangeteam.com/archive/2006/03/17/422350.aspx (Post Sp2 referral change is the same 2007)With the multiple mailboxes, Outlook simply connects to them directly.

Thanks Andy for the great explanation.Just in terms of the DC's - can you think of any reason why I would have multiple DC's listed in the Connection Status?

So there are 2 different domain controllers listed? Is that true if you switch Outlook to online mode? How about for other users? Any Outlook add-ins installed?I dont think there is something necessarily wrong, I just havent seen that.

Does it say "type" in the connection status?It could be a result of pulling information in from multiple domains in your environment, i.e. hitting a GC for look ups etc. I guess it would come down to how your AD Sites and Services are laid out also. Do you have one site for the entire domains or multiple sites?SF - MCITP:EMA, MCTS: MOSS 2007, OCS 2007, Exchange 2007

Hmmm...I tried it again at various times today and only one DC was listed (but many times as you said)....so I guess something weird was going on before...Thanks for the explanations!