Microsoft ISA Server 2006 can be used to secure access to Exchange Server 2003 servers by using Web publishing rules to make front-end servers for OWA, or RPC proxy servers, available on the Internet.

Using Enterprise Vault policy settings, you can configure direct connections to Enterprise Vault from Outlook 2003 in RPC over HTTP mode. Similarly, you can configure OWA clients to connect directly to Enterprise Vault for Archive Explorer and archive search client requests. If you configure direct connections to Enterprise Vault, then you need to configure your ISA Server to ensure that clients can access Enterprise Vault.

See the following technical note for detailed instructions on how to configure ISA Server 2006 for access to Enterprise Vault when using direct connections from OWA 2003 clients, and Outlook 2003 in RPC over HTTP mode:

http://www.symantec.com/docs/TECH53239

See About ISA Server with Enterprise Vault

See Configuring ISA Server 2006 for OWA 2007 or 2010 access to Enterprise Vault

See About configuring ISA Server 2006 for Outlook Anywhere client access to Enterprise Vault