Understanding the Microsoft Exchange Recipient

Applies to: Exchange Server 2010 SP3, Exchange Server 2010 SP2

Topic Last Modified: 2010-01-27

This topic describes the configuration and management of the Microsoft Exchange recipient. The Microsoft Exchange recipient is a special Microsoft Exchange Server 2010 recipient object that provides a unified and well-known message sender that differentiates system-generated messages from other messages. The Microsoft Exchange recipient is functionally equivalent to an internal postmaster. The Microsoft Exchange recipient replaces the System Administrator sender that was used for system-generated messages in earlier versions of Exchange. Messages from the Microsoft Exchange recipient display Microsoft Exchange as the sender. The types of messages sent by the Microsoft Exchange recipient include:

DSN messages
Journal reports
Quota messages
Agent-generated messages

Contents

Configuring the Microsoft Exchange Recipient

Internal and External Delivery of System Messages

Microsoft Exchange Recipient in Cross-Forest Scenarios

Configuring the Microsoft Exchange Recipient

Unlike a mailbox, mail user, or mail contact, the Microsoft Exchange recipient isn't a typical recipient object. The Microsoft Exchange recipient isn't managed by using the typical recipient tools found in the Exchange Management Console (EMC) or the Exchange Management Shell. However, you can use the Set-OrganizationConfig cmdlet in the Shell to perform the following configuration tasks:

Allow or prevent the application of the default e-mail address policy to the Microsoft Exchange recipient. By default, the default mail address policy is applied to the Microsoft Exchange recipient.
Configure a recipient object to receive messages that are sent to the Microsoft Exchange recipient. By default, no recipient is configured to receive messages that are sent to the Microsoft Exchange recipient.
Configure the e-mail addresses of the Microsoft Exchange recipient. This includes specifying a primary SMTP address.

Microsoft Exchange Recipient Parameters

The following table describes the Set-OrganizationConfig parameters used to configure the Microsoft Exchange recipient.

Microsoft Exchange recipient parameters in Set-OrganizationConfig

Parameter	Default value	Description
MicrosoftExchangeRecipientEmailAddresses	MicrosoftExchange329e71ec88ae4615bbc36ab6ce41109e@<Accepted Domain>. The <Accepted Domain> placeholder represents an accepted domain that's used in an e-mail address policy. For every accepted domain that's used in an e-mail address policy, there's a corresponding e-mail address.	The MicrosoftExchangeRecipientEmailAddresses parameter specifies one or more e-mail addresses for the Microsoft Exchange recipient. All valid Exchange 2010 e-mail address types may be used. You can specify multiple values for this parameter as a comma-delimited list. If the MicrosoftExchangeRecipientEmailAddressPolicyEnabled parameter is set to `$true`, the e-mail addresses are automatically generated by the default e-mail address policy, and you can't use the MicrosoftExchangeRecipientEmailAddresses parameter. E-mail addresses that you specify by using the MicrosoftExchangeRecipientEmailAddresses parameter replace any existing e-mail addresses that are already configured.
MicrosoftExchangeRecipientEmailAddressPolicyEnabled	`$true`	The MicrosoftExchangeRecipientEmailAddressPolicyEnabled parameter specifies whether the default e-mail address policy is automatically applied to the Microsoft Exchange recipient. The default value is `$true`. If this parameter is set to `$true`, Exchange 2010 automatically adds new e-mail addresses to the Microsoft Exchange recipient when e-mail address policies are added or modified in the Exchange organization. If this parameter is set to `$false`, you must manually add new e-mail addresses to the Microsoft Exchange recipient when e-mail address policies are added or modified. If you change the value of the MicrosoftExchangeRecipientEmailAddressPolicyEnabled parameter from `$false` to `$true`, any e-mail addresses that you defined by using the MicrosoftExchangeRecipientEmailAddresses parameter are preserved. However, the value of the MicrosoftExchangeRecipientPrimarySmtpAddress parameter reverts to MicrosoftExchange329e71ec88ae4615bbc36ab6ce41109e@<Accepted Domain in Highest Priority E-mail Address Policy>.
MicrosoftExchangeRecipientPrimarySmtpAddress	MicrosoftExchange329e71ec88ae4615bbc36ab6ce41109e@<Accepted Domain in Highest Priority E-mail Address Policy>	The MicrosoftExchangeRecipientPrimarySmtpAddress parameter specifies the primary return SMTP e-mail address for the Microsoft Exchange recipient. If the MicrosoftExchangeRecipientEmailAddressPolicyEnabled parameter is set to `$true`, you can't use the MicrosoftExchangeRecipientPrimarySmtpAddress parameter. If you modify the value of the MicrosoftExchangeRecipientPrimarySmtpAddress parameter, the value is automatically added to the list of e-mail addresses that are defined in the MicrosoftExchangeRecipientEmailAddresses parameter. The MicrosoftExchangeRecipientPrimarySmtpAddress parameter is meaningful only if the Microsoft Exchange recipient has more than one defined SMTP e-mail address. If the MicrosoftExchangeRecipientEmailAddresses parameter has only one defined SMTP e-mail address, the value of the MicrosoftExchangeRecipientPrimarySmtpAddress parameter and the MicrosoftExchangeRecipientEmailAddresses parameter are the same.
MicrosoftExchangeRecipientReplyRecipient	`$null`	The MicrosoftExchangeRecipientReplyRecipient parameter specifies the recipient that should receive messages that are sent to the Microsoft Exchange recipient. Typically, you would configure a mailbox to receive the messages that are sent to the Microsoft Exchange recipient. This parameter can take any of the following values for the specified recipient: Distinguished name (DN) Canonical name GUID Name Display name Alias Exchange DN Primary SMTP e-mail address If you don't configure a recipient for the Microsoft Exchange recipient, messages that are sent to the Microsoft Exchange recipient are discarded.

Internal and External Delivery of System Messages

The Microsoft Exchange recipient is used as the sender for system-generated messages sent to internal message senders. An internal sender is a recipient object that exists inside the Exchange organization. Specifically, the domain part of the primary SMTP e-mail address of the recipient object must be defined in the list of accepted domains for the Exchange organization.

When system-generated messages are sent to an external sender, the Microsoft Exchange recipient isn't used as the sender of the message. Instead, the e-mail address that's specified by the ExternalPostmasterAddress parameter in the Set-TransportConfig cmdlet is used. For more information, see Configure the External Postmaster Address.

However, under certain circumstances, the Microsoft Exchange recipient could be exposed to external recipients. These circumstances include but aren't limited to the following:

Alternative recipients
Externally forwarded meeting requests
External out-of-office notifications
Journal reports

Microsoft Exchange Recipient in Cross-Forest Scenarios

There's only one Microsoft Exchange recipient in an Exchange organization. Exchange 2010 determines that a message is sent from the Microsoft Exchange recipient by comparing the e-mail address of the message sender to the list of e-mail addresses that are defined by the MicrosoftExchangeRecipientEmailAddresses parameter. If Exchange 2010 determines that the sender is the Microsoft Exchange recipient, any messages from the sender are exempt from any configured message size limits that may exist in the Exchange organization.

However, in a cross-forest scenario, each forest has its own Microsoft Exchange recipient and its own message size limits. When messages are sent from the Microsoft Exchange recipient in the source forest, the target forest treats the sender as it would any other unauthenticated, external recipient. Even though the message is a system-generated message from the source forest, the message is still subject to any message size limits that are configured in the target forest.

To make sure that each forest can recognize messages that are sent from the Microsoft Exchange recipient in the other forest, you can configure the Microsoft Exchange recipient in each forest with an additional e-mail address that matches the primary e-mail address of the Microsoft Exchange recipient in the other forest. With this configuration, each forest can recognize messages that are sent from the Microsoft Exchange recipient in the other forest. This configuration correctly exempts messages that are sent from the Microsoft Exchange recipient in both forests from any message size limits.

However, this configuration introduces issues if either forest allows messages to be sent to the Microsoft Exchange recipient by using the MicrosoftExchangeRecipientReplyRecipient parameter. Because the Microsoft Exchange recipient in each forest is configured by using the e-mail addresses of the Microsoft Exchange recipients of both forests, any messages that are sent to the Microsoft Exchange recipient will never leave the local forest from which the messages are sent. The messages will be sent to the recipient that's specified by the MicrosoftExchangeRecipientReplyRecipient parameter in the local forest. If one administrator is responsible for the messaging administration of both forests, that administrator can read the messages that are sent to the Microsoft Exchange recipient in both forests. However, if different administrators are responsible for each forest, the administrator of one forest can't manage the messages that are incorrectly sent to the Microsoft Exchange recipient in the other forest.

For more information about how to administer Exchange 2010 in cross-forest scenarios, see "Understanding Multiple Forest Administration" in Deploy Multiple Forest Topologies.