For Environment with high percentage of clients are using Outlook 2003, and because there are some common client access considerations for outlook 2003 and Exchange 2010, then some preparations on client side should be done to cover all considerations as the following:
Exchange 2010 includes additional “out of the box” security for Client communications to the Exchange Server which is encryption between the Client and the Server which is enabled by default, for more information http://technet.microsoft.com/en-us/library/ee332317.aspx.
Prior to Outlook 2007, encryption was not enabled on the Client side, by default, however if profile for Outlook 2007 exist where encryption is disabled, or if Outlook 2003 profiles created with default settings are used with Exchange Server 2010, the connection will fail when Outlook attempts to connect to an Exchange Server 2010 mailbox, One or more of the following common error message will be displayed:
· Cannot start Microsoft Office Outlook. Unable to open the Outlook window. The set of folders could not be opened.
· Unable to open your default e-mail folders. The Microsoft Exchange Server computer is not available. Either there are network problems or the Microsoft Exchange Server computer is down for maintenance.
· The connection to the Microsoft Exchange Server is unavailable. Outlook must be online or connected to complete this action.
· Unable to open your default e-mail folders. The information store could not be opened.
· Outlook could not log on. Check to make sure you are connected to the network and are using the proper server and mailbox name. The connection to the Microsoft Exchange Server is unavailable. Outlook must be online or connected to complete this action.
There are several methods to work around this issue, from immediate manual change by the administrator or the user, to deployment of administrative templates or new profiles, each of these scenarios are documented in the following article: http://support.microsoft.com/kb/2006508.
In Exchange Server 2010 Service Pack 1, the RPC encryption requirement has been disabled, by default. Any new Client Access Servers (CAS) deployed in the organization will not require encryption. However, any CAS servers deployed prior to Service Pack 1, or upgraded to Service Pack 1, will retain the existing RPC encryption requirement setting. Also bear in mind disabling the RPC encryption requirement on a CAS server won't lower the security between Outlook 2007/2010 and any CAS server as RPC communication for these Outlook versions will remain encrypted.
It is recommended to apply Outlook Encryption Administrative template through GPO as described in Microsoft KB Article to enable Outlook RPC Encryption on all existing Outlook 2003 clients.
New Mail Notifications and UDP
Exchange 2010 no longer supports UDP for new mail notifications. However, Outlook 2003 relied primarily upon UDP notifications to display new messages and changes to folders. The result is that Outlook 2003 users will see delays in updates to folders and the Send/Receive process appears to take a long time.
The following article discusses the issue and two possible resolutions for the organization http://support.microsoft.com/kb/2009942.
The two available workarounds for this issue are as the following:
· Install Update Rollup 1 for Exchange 2010.
· User cached mode with outlook 2003 profile.
It is recommended to update all clients Outlook profile to use Cashed Mode.
Public Folder, Offline Address Book and Free/Busy
Outlook 2003 uses the Public Folders free/busy messages to determine availability in the Calendar and as the source for Offline Address Book synchronization. If Public Folders are not configured during Exchange Server 2010 setup, Offline Address Book and Free/Busy will not be available to Outlook 2003 users. These users will encounter connection errors.
If free/busy Public Folders folder is not replicated to Exchange Server 2010, users will encounter the following http://support.microsoft.com/kb/945602.
The following error message will be displayed if no public folder replicas for free/busy information were on Exchange 2010:
“0x8004010F” Error message:
· When outlook synchronizes an offline address book with Exchange Server 2007 and Exchange Server 2010, this if clients inside the organization or connected via VPN/RAS, and the organization uses a Proxy server, the Client Access Server should be listed in the “Bypass proxy server for local addresses” configuration http://support.microsoft.com/kb/939765.
· When try to synchronize address list on an Exchange Server while using Outlook 2003 http://support.microsoft.com/kb/905813.
Opening Additional Mailboxes
Opening other user’s folders or mailboxes are a common operation in the enterprise, Outlook 2003 users may encounter issues if the environment is not properly prepared for this use the following:
· Office Outlook 2003 does not connect to two or more additional mailboxes in a mixed Exchange 2007 and Exchange Server 2010 environment http://support.microsoft.com/kb/978777.
· An error occurs when an Exchange server 2003 user tries to open more that delegate mailboxes of Exchange Server 2010 in Outlook 2003 http://support.microsoft.com/kb/979690.
It is recommended to upgrade all Outlook 2007 to Outlook 2007 Service Pack 2 or higher http://support.microsoft.com/default.aspx?scid=kb;EN-US;924470.
RPC over HTTP Connectivity
The following article discusses issues with Outlook 2003 connectivity when the RPC proxy server extensions do not load correctly, and this article applied to Exchange 2010 connections http://support.microsoft.com/kb/919092.
If the mentioned error shown while migration pilot one of the proposed solution will be tested to solve the issue.
Integration features between Outlook 2003 and Office Communicator and functionality with Office Communication Server have been documented in the following documents:
· The presence information for a Communications Server user may not appear, or may appear intermittently, in Outlook 2003 Service Pack 2 or in Outlook 2007 http://support.microsoft.com/kb/968099.
· Communicator does not update the free/busy information as scheduled http://support.microsoft.com/kb/941103.
It is recommended to follow the solutions in KB article “http://support.microsoft.com/kb/968099” to avoid the related presence issue, also it is recommended to upgrade all Outlook 2003 clients to Outlook 2003 Service Pack 3 because Outlook 2003 Service Pack 2 is no longer supported, this beside apply Outlook 2003 fix http://support.microsoft.com/?id=971366 that will solve some Outlook issues as listed in the KB article.