1. Check that prerequisite tasks for setting up RPC over HTTP on Exchange Servers and client computers are completed.  See "Prerequisite tasks" below.
2. On the Enterprise Vault server, enable RPC over HTTP in the Exchange Desktop Policy.  See "Configuring Enterprise Vault Exchange Desktop policies" below.

1. On the Exchange 2007 CAS server computers, set up RPC over HTTP (Outlook Anywhere) as described in the Microsoft documentation.
   https://technet.microsoft.com/en-us/library/bb123889.aspx
    
2. On desktop computers, enable Outlook for RPC over HTTP (Outlook Anywhere) as described in the Microsoft documentation.
   https://office.microsoft.com/en-gb/outlook-help/use-outlook-anywhere-to-connect-to-your-exchange-server-without-a-vpn-HP010355551.aspx
    
3. Configure the Enterprise Vault server to archive Exchange Server mailboxes.
    
4. Installed Enterprise Vault Add-Ins (any type) on the desktop computers.

Configuring Enterprise Vault Exchange Desktop policies

Settings in Enterprise Vault Exchange Desktop Policy enable RPC over HTTP connections and also allow the ability to restrict the availability of Enterprise Vault functionality to RPC over HTTP Outlook users. To modify Exchange Desktop Policy settings:

Edit the following settings as required. Double-click a setting to edit it, or click it once to select it and then click Modify:

a) RPC over HTTP connection.
* Set this to Direct to enable Exchange Server 2007 RPC over HTTP connections to Enterprise Vault.
   Note: By setting this value to Direct, external requests will be made to the internal EV Server name.  If utilizing a Firewall to pass the request, this must be published externally.  
* Set this to Use Proxy to specify an alternative URL for the Enterprise Vault server. This enables the client to route all Enterprise Vault requests to the Enterprise Vault server using the URL specified in the RPC over HTTP Proxy URL setting.  
 
b) RPC over HTTP Proxy URL. When setting RPC over HTTP connection to "Use Proxy", this specifies the URL used to contact the EV server while in RPC over HTTP mode.  This can be a valid published external address that a firewall will accept and route this internally. 

Examples

Set this value to https://MyExternalWebAddress.com/EnterpriseVault
Set the active firewall to accept calls to https://MyExternalWebAddress.com/EnterpriseVault and route these to https://EVServerName/EnterpriseVault

To test routing, perform the following:

From an external workstation, open Internet Explorer (IE) and type the external URL in the address. (Ex. https://MyExternalWebAddress.com/EnterpriseVault)
If successfully routed, a prompt for credential should be available and the Enterprise Vault Webapp Homepage will open.

Note: Assistance with configuring Firewall or ISA technology is outside the scope of Enterprise Vault Technical Support.  Please refer to a Firewall Administrator or ISA Administrator for further assistance.

c) RPC over HTTP restrictions controls the functionality available in the Enterprise Vault Add-Ins when using RPC over HTTP. Select one of the following values for this setting:

None - All Enterprise Vault client functionality is available.
Disable User Extensions - RPC over HTTP working is not enabled in the Enterprise Vault Add-Ins. This is the default value.
Disable Vault Cache only* - Vault cache is disabled.
Disable PST Import only* - Client-side PST migration is disabled.  Note that currently you cannot use client-side PST migration to migrate PST files that reside on mapped network drives when using an RPC client, even if this setting is enabled.
Disable Vault Cache and PST Import* - Vault cache and client-side PST migration are disabled.

Note: * denotes EV 8.0 and above only.

1. In the left pane of the Administration Console, expand the hierarchy until Policies is visible.
    
2. Expand Policies => Exchange.
   - For Enterprise Vault (EV) 2007 and below, open the Exchange Mailbox Policy
   - For Enterprise Vault (EV) 8.0 and above, open the Exchange Desktop Policy.
    
3. In the right-hand pane, double-click the name of the policy to edit. The policy's properties are displayed.
    
4. Click the Advanced tab.
    
5. Next to List settings from, select Outlook.
    
6. Any settings that are modified are applied to users' mailboxes during the next synchronization run of the Exchange Mailbox Archiving task. If changes must be applied before the next synchronization, run Synchronize, which is on the Synchronization tab of the Exchange Mailbox Archiving task's properties.