Exchange 2016: Recipients

In Exchange Server 2016 all kind of recipients, like mailboxes and mail users, where people and resources send and receive messages are the main of any messaging and collaboration system.


In an Exchange organization, such people and resources are called as recipients. A recipient is any kind of mail-enabled object in Active Directory to that Microsoft Exchange might deliver or route messages.


  1. Exchange recipient types

  3. Recipients documentation


Exchange recipient types


Exchange includes of several explicit recipient categories. Evert recipient type is verified in the Exchange admin center (EAC) and has a very unique value in the RecipientTypeDetails property characteristics


In the Exchange Management Shell, the use of explicit recipient categories has the following advantages:


  • At a glance, you might differentiate among various recipient categories.
  • You may search and sort by each recipient category.
  • You may more easily conduct bulk management processing and operations for selected recipient categories.
  • You may more easily able to access the recipient properties as the EAC uses the recipient categories to render distinguish property pages. For instance, the resource capacity is displayed for a room mailbox, however, isn’t present for a user mailbox.


The following given table lists the available recipient categories. All these recipient categories are discussed in more detail later under this topic.


Recipient category Detail Description
Dynamic distribution group A distribution group which uses recipient filters and such conditions to derive and orient its membership at the time messages are been sent.
Equipment mailbox A resource mailbox which is assigned to a resource which is not location-specific, like a portable computer, microphone, projector, or a company car.  The equipment mailboxes might be included as resources in addressing requests, offering a simple and efficient approach of using resources for end users.
Linked mailbox A mailbox which is assigned to an individual user in a segregated, trusted forest.
Mail contact A mail-enabled Active Directory contact which contains information regarding the people or organizations which exist outside the Exchange organization. Every mail contact is equipped with an external email address. Every messages sent to the mail contact are directed to this external email address.
Mail forest contact A mail contact which represents a recipient object from another forest. Mail forest contacts are generally created by Microsoft Identity Integration Server (MIIS) synchronization.
Mail user A mail-enabled Active Directory user which represents a user outside the Exchange organization. Every mail user has an external email address. Every messages sent to the mail user are routed and directed towards this external email address.
A mail user is very similar to a mail contact, except that a mail user is quip with Active Directory logon credentials and may access resources.
Mail-enabled non-universal group Activated mail-enabled Active Directory global or local groups object. Mail-enabled non-universal groups were discontinued over Exchange Server 2007 and might exist only in case they were migrated from Exchange 2003 or earlier versions of Exchange. You cannot use Exchange Server 2013 to build non-universal distribution groups.
Mail-enabled public folder An Exchange public folder which is configured to receive messages.
Distribution groups A distribution group is a mail-enabled Active Directory distribution group object which can be used only for message distribution to a group of recipients.
Mail-enabled security group A mail-enabled security group is an Active Directory universal security group object which can be used to allocate access permissions to resources in Active Directory and may also be used to distribute messages.
Microsoft Exchange recipient A special recipient object which provides a unified and well-known message sender which differentiates system-generated messages from other messages. It replaces the System Administrator sender used for system-generated messages in previous versions of Exchange.
Room mailbox A resource mailbox which is assigned to a meeting location, like a auditorium, conference room, or training room. Room mailboxes might be included as resources in addressing requests, offering a simple and efficient way of organizing meetings for your users.
Shared mailbox A mailbox which is not primarily concerned with a single user and is usually configured to permit access for multiple users.
Site mailbox A mailbox consisting of an Exchange mailbox to save and store email messages and a SharePoint site to save and store documents. Users might access both email messages and documents via using the same client interface.
User mailbox A mailbox which is assigned to an individual user in your Exchange organization. It generally contains messages, calendar items, tasks, contacts, documents, and other crucial business data.
Office 365 mailbox Over hybrid deployments, an Office 365 mailbox includes of a mail user which exists in Active Directory on-premises and an associated cloud mailbox which exists in Exchange Online.
Linked user A linked user is a user whose mailbox is usually resides in a different forest rather than the forest in which the user resides.



Important note:

Mail forest contacts are read-only recipient objects which are updated only via MIIS or similar custom synchronization. You might not use the EAC or the Exchange Management Shell to tunicate or modify a mail forest contact.



Mailboxes are the very common recipient category used by information workers over an Exchange organization. Every mailbox is associated with an Active Directory user account. The user might use the mailbox for receiving and sending messages, and to save or store messages, appointments, notes, tasks, and documents. Mailboxes are the mainly messaging and collaboration tool  used for the users in your Exchange organization.


Components of the Mailbox

Every mailbox are inclusive of an Active Directory user and the mailbox data which is stored in the Exchange mailbox database (as depicted in the following figure).  Every configuration data for the mailbox is saved and stored in the Exchange attributes of the Active Directory user object. The mailbox database includes the actual data which is in the mailbox related with the user account.


Important Note:

While you create a mailbox for a new novice or existing user, the Exchange attributes needed for a mailbox are added on to the user object present in the Active Directory. The affiliated mailbox data is not created till the mailbox either receives a message or the user signs in to it.


Mailbox components


 Warning Alert :

In case you remove a mailbox, the mailbox data saved and stored over the Exchange mailbox database is marked for deletion and the related user account is also deleted from Active Directory. For retaining the user account and delete only the mailbox data, you should disable the mailbox.


Mailbox categories

Exchange supports and backs the following mailbox categories:


  • User mailboxes User mailboxes are allocated to individual users located in your Exchange organization. User mailboxes offer your users with a rich collaboration platform. Users might send and receive messages, control and manage their contacts, schedule meetings, and sustain to maintain a task list. They might also have voice mail messages delivered to their respective mailboxes. User mailboxes are very commonly used mailbox categories and are generally the mailbox type allocated to users in your organization.

  • Linked mailboxes Linked mailboxes are those mailboxes that are accessed via users in a separate, trusted forest. Linked mailboxes might be essential for organizations that implements Exchange in a resource forest. The resource forest scenario permits an organization to centralize Exchange in a single forest, while permitting access to the Exchange organization with user accounts in several (one or more) trusted forests.

As previously stated, every mailbox must have a user account related with it. However, the user account that accesses the linked mailbox does not exist in the forest where Exchange is implemented and deployed. Hence, a disabled user account which exists in the same forest as Exchange is associated with each linked mailbox. The following figure describes the relationship among the linked user account used to access the linked mailbox and the disabled user account in the Exchange resource forest related with the linked mailbox.


Linked mailbox




  • Office 365 mailboxes While you create an Office 365 mailbox over Exchange online in a hybrid implementation, the mail user is build in Active Directory on-premises. Directory synchronization, if it is configured, automatically synchronizes this new novice user object to Office 365, where it’s converted over to a cloud mailbox in Exchange Online. You might create Office 365 mailboxes as routine and regular user mailboxes, resource mailboxes for meeting rooms and equipment, shared mailboxes.

  • Shared mailboxes Shared mailboxes are not primarily related with individual users and are usually configured to permit access by multiple users.Though it’s possible to allocate additional users the logon access permissions for any mailbox category, shared mailboxes are dedicated for such functionality. The Active Directory user collaborated with a shared mailbox should be a disabled account. After you build a shared mailbox, you should assign permissions to all users which require access to the shared mailbox.

  • Resource mailboxes Resource mailboxes are special kind of mailboxes designed to be used for an organize scheduling resources. Such as all mailbox types, a resource mailbox has a related Active Directory user account, however it must be a disabled account. The following are the categories of resource mailboxes:

i)- Room mailboxes These mailboxes are allocated to meeting locations, like conference rooms, training rooms and auditoriums.

ii)- Equipment mailboxes These mailboxes are allocated to resources which are not location-specific, like portable computers, microphones, projectors, or company cars.


You might include both categories of resource mailboxes in meeting requests, providing a simple and efficient approach for your users to use resources. You might configure resource mailboxes to automatically process incoming meeting requests based on the resource booking policies which are defined by the resource owners. For instance, you can configure a conference room to by default accept incoming meeting requests except recurring meetings which can be subject to approval by the resource owner.


System mailboxes

System mailboxes are build by Exchange in the root domain of the Active Directory forest while installation. Users or administrators might not sign in to these mailboxes. System mailboxes are generated for Exchange features like Unified Messaging (UM), message approval, migration, and In-Place eDiscovery. This table lists brief information regarding system mailboxes as they’re displayed in Active Directory.


Mailbox Name
Organization SystemMailbox {bb558c35-97f1-4cb9-8ff7-d53741dc928c}
Message approval SystemMailbox {1f05a927-xxxx xxxx – xxxx –xxxxxxxxxxxx}
where x is a randomly assigned and unique number for each Exchange forest
UM data storage SystemMailbox {e0dc1c29-89c3-4034-b678-e6c29d823ed9}
Discovery DiscoverySearchMailbox {D919BA05-46A6-415f-80AD-7E09334BB852}
Federated email FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042
Migration Migration.8f3e7716-2011-43e4-96b1-aba62d229136



In case you wish to decommission the last Mailbox server in your Exchange organization, you must first disable these system mailboxes by utilizing the Disable-Mailbox cmdlet. While you decommission a Mailbox server which contains these system mailboxes, you must move the system mailboxes to another Mailbox server to ensure that you don’t lose functionality.


Planning for mailboxes

Mailboxes are generated in mailbox databases on Exchange servers which have the Mailbox server role installed. To help offer a reliable and effective platform to your mailbox users, good detailed planning for the implementation of Mailbox servers and databases is necessary.


Distribution groups

Distribution groups are mail-enabled Active Directory group objects which are primarily used for distributing messages to several recipients. Any such recipient category can be a member of a distribution group.


Kindly Note :

The terminology differences among Active Directory and Exchange. In Active Directory, a distribution group known to any group which does not possesses a security context, whether it is a mail-enabled or not. In Exchange, all mail-enabled groups are known as distribution groups, irrespective of whether they have a security context or not.


Exchange supports and backs the following categories of distribution groups:


  • Distribution groups These are Active Directory universal distribution group objects which are mail-enabled. They might be used only to distribute messages over to a group of recipients.

  • Mail-enabled security groups they are Active Directory universal security section group objects which are mail-enabled. They might be used to allocate access permissions to resources in Active Directory and might also be used to distribute messages.

  • Mail-enabled non-universal groups are Active Directory global or local section or group objects which are mail-enabled. You may create or mail-enable only universal distribution section or groups. You might have mail-enabled groups that were moved from earlier versions of Exchange which aren’t universal groups. Such groups might be managed by using the EAC or the Exchange Management Shell.


Please Note:

For converting a domain-local or a global group over to a universal group, you might use the Set-Group cmdlet over the Exchange Management Shell.



Dynamic distribution groups

Dynamic distribution groups or sections are distribution sections whose membership depends upon specific recipient filters instead of a defined set of recipients.


Unlike regular distribution groups or section, the list of membership for dynamic distribution groups is calculated every time a message is being sent to them, depending upon the filters and conditions which you mentioned. When an email message is being sent to a dynamic distribution group, it is delivered to all recipients over the organization which matches the criteria defined for that dynamic distribution group.


Kindly Note:

A dynamic distribution group consists of any recipient in Active Directory which has attributes which matches the group’s filter at the time a message is sent. In case a recipient’s properties are edited and modified to tally the group’s filter, which recipient could not deliberately become a group member and begin receiving messages which are sent to the dynamic distribution group. Well-defined and declared consistent account provisioning processes might reduce the occurrences of the chances of arising of such issue.


To help you generate recipient filters for dynamic distribution groups, you might use precanned filters. A precanned filter is a popularly used filter which you can use to meet a various kinds of recipient-filtering criteria. You may use these filters to mention the recipient categories that you wish to include in a dynamic distribution group. Moreover, you may also mention a list of conditions which the recipients should meet. You might create precanned conditions depending on the following characteristics:


  • Custom attributes 1–15
  • Company
  • State or province
  • Department
  • Recipient container


You may also specify conditions depending on recipient properties other than those earlier listed. To get this done, you must use the Exchange Management Shell to build a custom query for the dynamic distribution group. Note that the filter and condition settings and configuration for dynamic distribution groups which have custom recipient filters might be managed only by using the Exchange Management Shell.


Mail contacts

Mail contacts generally contain information regarding people or organizations which exist outside your Exchange organization. Mail contacts may appear in your organization’s shared address book (also known as the global address list or GAL) also other address lists, and might be added as members to distribution groups. Every contact has an external email address, and every email messages which are sent to a contact are automatically by default forwarded to that address. Contacts are ideal for indicating people external to your Exchange enterprises (in the shared address book) who do not require access to any internal resources. The following are mail contact categories:


  • Mail contacts are mail-enabled Active Directory contacts which contain information regarding the people or organizations which exist outside your Exchange organization.

  • Mail forest contacts represent recipient objects from other forest. Such contacts are generally created by directory synchronization. The Mail forest contacts are read-only recipient objects which can be updated or deleted only by means of synchronization. You are not allowed to use Exchange management interfaces to edit or modify or remove a mail forest contact.



Mail users

Mail users are same as mail contacts. They both have external email addresses, both include information about people outside your Exchange organization, and both might be displayed in the shared address book and other address lists. But, unlike a mail contact, mail users might have Active Directory logon credentials and may access resources to which they are allocated permissions.


In case a person external to your enterprise requires access to resources present on your network, you must create a mail user instead of a mail contact. For instance, you may wish to generate mail users for short-term consultants who needs access to your server infrastructure, however, who is going to use their own external addresses.


Another type of scenario is to create mail users present in your organization for users who you don’t wish to retain or maintain an Exchange mailbox. For instance, after an acquisition, the acquired organization may maintain their separate isolating messaging infrastructure, however may also need access to resources over your network. For those users, you might wish to create mail users rather than of mailbox users.


Please Note:

In the EAC, you might use the Recipients > Contacts page to make and manage mail users. There is no separate page is available for mail users.


Mail-enabled public folders

Public folders are oriented to serve as a repository for information shared among multiple users. Mail-enabling a public folder offers an extra level of features and functionality to users. Moreover, to being able to post messages to the folder, users might send email messages to, and at times receive email messages from, the public folder. Every mail-enabled folder consists of an object in Active Directory which stores its address book name, email address, and other mail-related attributes.


You might manage public folders by utilizing either the EAC or the Exchange Management Shell.


Microsoft Exchange recipient

The Microsoft Exchange recipient is a special kind of recipient object that offers a unified and well-known message sender which differentiates system-generated messages from another message. It substitutes the System Administrator sender which was used for system-generated messages in previous versions of Exchange.


The Microsoft Exchange recipient is not a usual recipient object, such as a mail user, mailbox, or mail contact, and it is also not managed or controlled by using the general recipient tools. But, you might use the Set-OrganizationConfig cmdlet in the Exchange Management Shell to configure the Microsoft Exchange recipient.


Please Note:

While system-generated messages are being sent to an external sender, the Microsoft Exchange recipient is not utilized as the sender of the message. Rather, the email address mentioned by the ExternalPostmasterAddress parameter in the Set-TransportConfig cmdlet is used.


Recipients documentation

The following table is inclusive of links to topics which will help you learn about and manage Exchange recipients.


Topic Details Description
Create user mailboxes Learn how to create user mailboxes using the Exchange admin center or the Exchange Management Shell.
Manage user mailboxes Learn how to create user mailboxes, change mailbox properties, and bulk-edit selected properties for multiple mailboxes.
Manage distribution groups Learn how to create and manage distribution groups, and create a group naming policy for your organization.
Manage dynamic distribution groups Learn how to create dynamic distribution groups and manage dynamic distribution group properties, such as using custom attributes and other properties to determine group membership.
Manage mail contacts Learn how to create and manage mail contacts.
Manage mail users Learn how to create and manage mail users.
Create and manage room mailboxes Learn how to create room mailboxes and manage room mailbox properties, such as enabling recurring meetings and configuring booking and scheduling options.
Manage equipment mailboxes Learn how to create equipment mailboxes, configure booking and scheduling options, and manage other mailbox properties.
Disconnected mailboxes Learn about the two types of disconnected mailboxes and how to work with them.
Custom attributes Learn how to add information about a recipient by using custom attributes.
Filters in recipient Exchange Management Shell commands Learn how to use precanned or custom filters with commands to filter a set of recipients.
Manage permissions for recipients Learn how to use the EAC or the Exchange Management Shell to assign permissions to users and groups.
Automatic mailbox distribution Learn about how automatic mailbox distribution works and how to control which mailbox databases are selected for new and moved mailboxes.

Kristin is a content strategist at Techarex Networks. Kristin follows the B2B technology space closely and loves to write on the latest changes in technology, futuretech and fixes for day to day how to issues. Besides writing Kristin also loves music, moves and skating.

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