How to Enable Outlook Web Access Data Compression


Topic Last Modified: 2006-08-17

Outlook Web Access supports data compression, which is optimal for slow network connections. Depending on the compression setting you use, Outlook Web Access compresses static Web pages, dynamic Web pages, or both. The following table lists the compression settings that are available in Microsoft® Exchange Server 2003 for Outlook Web Access.

Compression settings for Outlook Web Access

Compression setting Description


Compresses both static and dynamic pages.


Compresses only static pages.


No compression is used.

To use data compression for Outlook Web Access in Exchange Server 2003, verify that your organization meets the following prerequisites:

  • The Exchange server that users authenticate against for Outlook Web Access must be running Microsoft Windows Server™ 2003.

  • Your users' mailboxes must be on Exchange 2003 servers. (If you have a mixed deployment of Exchange mailboxes, you can create a separate virtual server on your Exchange server just for Exchange 2003 users and enable compression on it.)

  • Client computers must be running Microsoft Internet Explorer version 6 or later. The client computers must also be running Microsoft Windows® XP or Microsoft Windows 2000 Server and have installed on them the security update that is discussed in Microsoft Security Bulletin MS02-066, "Cumulative Patch for Internet Explorer (Q328970)."

    If a user does not have a supported browser for compression, the client computer still operates normally.
  • You may need to enable HTTP 1.1 support through proxy servers for some dial-up connections. (HTTP 1.1 support is required for compression to function correctly.)

  1. Start Exchange System Manager.

  2. In the details pane, expand Servers, expand the server you want, and then expand Protocols.

  3. Expand HTTP, right-click Exchange Virtual Server, and then click Properties.

  4. In Exchange Virtual Server Properties, on the Settings tab, under Outlook Web Access, use the Compression list to select the compression level you want (None, Low, or High).

  5. Click Apply, and then click OK.

For information about managing and configuring Outlook Web Access, see the following topics in the Exchange Server 2003 Client Access Guide:

  • Configuring Outlook Web Access

  • Managing Outlook Web Access


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