How to Enable or Disable Voice Messages from Anonymous Callers

Microsoft Exchange Server 2007 will reach end of support on April 11, 2017. To stay supported, you will need to upgrade. For more information, see Resources to help you upgrade your Office 2007 servers and clients.


Applies to: Exchange Server 2007, Exchange Server 2007 SP1, Exchange Server 2007 SP2, Exchange Server 2007 SP3

Topic Last Modified: 2007-08-19

This topic explains how to use the Exchange Management Console and the Exchange Management Shell to allow a Microsoft Exchange Server 2007 recipient who is enabled for Unified Messaging (UM) to receive voice messages from anonymous callers or to prevent them from doing so. By default, when a user is enabled for Unified Messaging, they can receive calls that are anonymous and do not contain caller ID information.

In most cases, calls that are received by a Unified Messaging server contain a caller ID that can be used to determine the source of the incoming call. However, incoming calls may not include caller ID information for the following reasons:

  • Your organization's telephony equipment is configured not to include caller ID information.

  • The incoming call is from a mobile or external telephone.

  • The caller has disabled caller ID on their telephone.

Because the Allow diverted calls without a caller ID to leave a message option is enabled by default, a UM-enabled user can receive a voice message even if caller ID information is not included. If the Allow diverted calls without a caller ID to leave a message option is disabled and the UM-enabled user receives a call that does not include a caller ID, the call will be identified as anonymous, and the UM-enabled user will not receive a voice message.

To perform the following procedures, the account you use must be delegated the Exchange Recipient Administrator role.

For more information about permissions, delegating roles, and the rights that are required to administer Exchange 2007 see Permission Considerations.

Also, before you perform these procedures, confirm the following:

  • The Exchange recipient has an Exchange 2007 mailbox.

  • The Exchange 2007 recipient is enabled for Unified Messaging.

  • A UM dial plan has been created.

  • A UM mailbox policy has been created.

  • The extension number that is assigned to the Unified Messaging user is valid according to the UM dial plan that is defined.

  1. In the console tree of the Exchange Management Console, expand the Recipient Configuration node.

  2. In the result pane, select the user's mailbox that you want to view.

  3. In the action pane, click Properties.

  4. On the Mailbox Features tab, click Unified Messaging, and then click Properties.

  5. On the Unified Messaging Properties page, do one of the following:

    • To enable voice messages from anonymous callers, select the Allow diverted calls without a caller ID to leave a message check box.

    • To disable voice messages from anonymous callers, clear the Allow diverted calls without a caller ID to leave a message check box.

  6. Click OK to accept your changes.

  • Run the following command:

    Set-UMMailbox -Identity -AnonymousCallersCanLeaveMessages <True | False>

For more information about syntax and parameters, see Set-UMMailbox.