I have two Exchange 2010 servers in two locations (and one Exchange 2007 at one of the places but this one is not really in use nor causing any problems) - one server per site (say site A and site B). Sites are on different network ranges and there is a routed tunnel set up between sites. Users' mailboxes are spread out between those two servers so users access to their mail locally rather than through slow WAN link. There is a DC and DNS server per site, and DNS resolves names correctly.

The problem is with Outlook account configuration - no matter what I do, when the site B Exchange server name is entered in Outlook, Outlook resolves the name to the Exchange server from site A. I tried using the server name (Company-EX02), FQDN (Company-EX02.domain.local) and the IP address but nothing makes any difference (this happens from either site, not just site B).

I might be wrong but as the connection speed seems to be worse now (I did not do proper tests before the change so can't really say for sure) I have a feeling the traffic still goes through slow WAN link but actually multiple times - first the user's mail client speaks to EX01, then EX01 speaks to EX02, then data is moved back to EX01 and finally to user at site B.


The way I read it, you have 2 mailbox databases - one in Site A for the users in Site A and another for Site B for the users in Site B. What's the output of Get-MailboxDatabase MailboxDBInSiteB | fl RpcClientAccessServer? Is it the CAS in Site A or Site B?

It should be the CAS in site B, but if it isn't try the cmdlet Set-MailboxDatabase MailboxDBInSiteB -RpcClientAccessServer CASInSiteB.

  • Spot on! RpcCAS was pointing to Company-EX01 so I ran the second command and it resolves the server name correctly. Thank you very much !!! – xor.cat May 25 '11 at 11:36

What roles are installed on the three servers?

In Exchange 2010, internal Outlook clients (i.e. RPC connections) don't connect anymore to mailbox servers, but to Client Access ones; if the CAS role isn't there (or is not configured correctly), it's perfectly possible for clients to connect to the wrong server.

  • Site A - There are Mailbox, Client Access, Hub Transport and Management Tools installed at Site B – xor.cat May 25 '11 at 10:12
  • Both Sites are configured to Maiblox role, CAS, and Hub Transport as well as Management tools – xor.cat May 25 '11 at 10:14

Exchange is site-aware. Do you have your network-to-site definitions set up correctly in AD Sites & Services? Also worth checking if you have assigned the "Global Catalog" role to at least one DC at each site - it will help keep intersite GC query traffic down which is initiated by Outlook and Exchange.

  • Sorry about my lousy comments but i can't get used to the fact pressing Enter add a comment rather than goes to another line. There is Global Catalog on DC at each site. And yes, AD Sites and Services are configured and aware of each site / subnet / site link. – xor.cat May 25 '11 at 10:25

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