Applies to: Exchange Server 2007 SP3, Exchange Server 2007 SP2, Exchange Server 2007 SP1, Exchange Server 2007
Topic Last Modified: 2007-07-31

This topic explains how to use the Exchange Management Console or the Exchange Management Shell to add recipients to the Recipient Block list for recipient filtering. You can configure recipient filtering to block inbound messages for up to 100 specific recipients in your organization. If an inbound message contains a recipient that is on the Recipient Block list, the computer that has the Edge Transport server role installed sends a "550 5.1.1 User unknown" Simple Mail Transfer Protocol (SMTP) session error to the sending system.

Important:
The Recipient Block list reads from a recipient information cache on the local Edge Transport server. The recipient information cache is updated every four hours. Therefore, if you add recipients to the Recipient Block list, it may be up to four hours before the recipient information cache is updated. To update the recipient information cache immediately after you add recipients to the Recipient Block list, restart the Microsoft Exchange Transport service on the Edge Transport server on which recipient filtering is being run.

Important:

The Recipient Block list reads from a recipient information cache on the local Edge Transport server. The recipient information cache is updated every four hours. Therefore, if you add recipients to the Recipient Block list, it may be up to four hours before the recipient information cache is updated. To update the recipient information cache immediately after you add recipients to the Recipient Block list, restart the Microsoft Exchange Transport service on the Edge Transport server on which recipient filtering is being run.

Before You Begin

To perform the following procedures on a computer that has the Edge Transport Server role installed, you must log on by using an account that is a member of the local Administrator's group on that computer.

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

You have reviewed Anti-Spam and Antivirus Functionality to understand the general strategy for configuring all anti-spam agents so that they work together efficiently for your organization.
You have read Recipient Filtering.

Procedure

To add recipients to the Recipient Block list by using the Exchange Management Console

In the Exchange Management Console, click Edge Transport.
In the work pane, click the Anti-spam tab, and then select Recipient Filtering.
In the action pane, select Properties, and then on the Recipient Filtering Properties page, click the Blocked Recipients tab.
To automatically block messages to recipients that do not exist in your organization or recipients that require sender authentication, select the Block messages sent to recipients not listed in the recipient list check box.

For more information about how to require sender authentication, see How to Configure Anti-Spam Features on a Mailbox.
To enable recipient blocking, select the Block the following recipients check box.
In the text box, type the SMTP address for a recipient, and then click Add to add that recipient to the Recipient Block list.
Click OK to save your changes and close the dialog box, or click Apply to save your changes without closing the dialog box.

To add recipients to the Recipient Block list by using the Exchange Management Shell

To enable recipient blocking, run the following command:
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Set-RecipientFilterConfig -BlockListEnabled $true

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Set-RecipientFilterConfig -BlockListEnabled $true

To add recipients to the Recipient Block list, run the following command:

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Set-RecipientFilterConfig -BlockedRecipients <SMTPAddress>

For example, to add recipient1@contoso.com to the Recipient Block list, run the following command:

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Set-RecipientFilterConfig -BlockedRecipients recipient1@contoso.com

Note:
You can add multiple recipients by putting a comma between each SMTP address. For example recipient1@contoso.com, recipient2@contoso.com. The BlockedRecipients parameter takes multiple values. When you pass a value to the BlockedRecipients parameter, the existing value is replaced with the new value. For more information about how to add or remove values from multivalued properties, see Modifying Multivalued Properties.

Note:

You can add multiple recipients by putting a comma between each SMTP address. For example recipient1@contoso.com, recipient2@contoso.com. The BlockedRecipients parameter takes multiple values. When you pass a value to the BlockedRecipients parameter, the existing value is replaced with the new value. For more information about how to add or remove values from multivalued properties, see Modifying Multivalued Properties.

To block messages to recipients that do not exist in your organization, run the following command:
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Set-RecipientFilterConfig -RecipientValidationEnabled $true

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Set-RecipientFilterConfig -RecipientValidationEnabled $true

For detailed syntax and parameter information, see Set-RecipientFilterConfig.

For More Information

For more information about how to configure recipient filtering, see the following topics: