In the following example configuration there are no front-end Exchange Servers.

Figure: Back-end only Exchange Server 2000/2003 OWA configuration

Instead, users connect to an Exchange Server that is configured as a back-end Exchange Server. This configuration can provide more security. You can force users to use IWA authentication instead of basic authentication when the clients connect to the Exchange Servers. Anonymous authentication is used for the connection between the Exchange Server and the Enterprise Vault server. The Data Access account is configured to manage the anonymous connections.

See Configuring Enterprise Vault for anonymous connections.

Connecting OWA clients directly to the back-end Exchange Server is a good way to troubleshoot problems with Enterprise Vault in the OWA clients. This test is also useful after you have upgraded the Enterprise Vault OWA Extensions, or made changes to OWA files on the Exchange Server.

As in previous configurations, an Enterprise Vault Exchange Desktop policy setting can be used to enable OWA 2003 clients to connect directly to the Enterprise Vault server. Direct connections are used when users start Archive Explorer or an archive search from their OWA client.

If direct connections are not configured (which is the default for Exchange Server 2003 OWA), then only the Exchange Server 2003 back-end server needs to be published.

See About ISA Server with Enterprise Vault.

See About OWA configurations for Enterprise Vault