Exchange Server 2007 - Recipient Types

Microsoft Exchange Server 2007 - Recipient Types

For old timers, Microsoft's new way of categorizing Exchange 2007 recipients takes some getting used to.  Part of the problem is that there are just more and more types of recipient, each of which needs a new name.  Another factor seems to be that in Exchange 2007, Microsoft have decided to 'bite the bullet' and re-define old names that are misleading, or no longer make sense.  Rather like 100 years ago when they changed the name of the horseless carriage to the car. 

The final factor may be my prejudice for short names such as 'distribution list', whereas Americans in general, and Microsoft in particular, prefer long names such as 'Mail-enabled universal distribution group'. 

Exchange 2007 Recipient Types

• Mailbox User
• Mail user
• Mail contact
• Mail-enabled universal distribution group (DL)
• Dynamic distribution group
• Room mailbox (Resource object)
• Practical Tasks - How to create Exchange 2007 Recipients

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Three questions to make sense of Exchange's recipient naming policy

1. Is an Active Directory account needed for this recipient type?
2. Does the Exchange 2007 database store this email?
3. Are multiple users involved?

Descriptions of the Main Recipient Types

Mailbox User
A mailbox user describes the classic Microsoft Exchange recipient.  They have an Active Directory account, and a mailbox which connects to a database in your Exchange organization.  85% of all Exchange 2007 email accounts are of this MAPI type.  As you may anticipate, a user's mailbox typically contains email messages, calendar items, contacts and maybe even voicemail.  In Exchange Server 2003 this recipient was called a Mailbox-enabled User, it is also referred to as User Mailbox.

While I have been rude about Microsoft's written description of Exchange 2007 recipients, I would like to praise their graphics.  If a picture is worth a thousand words, then an icon must be worth a hundred words.  This is how you create a User mailbox

Mail user
A mail user also has an Active Directory logon account, but is configured with an email address outside your Exchange organization.  A mail user does not have a mailbox in your Exchange database; instead they send and receive their email via an external email address such as recipient@gmail.com.  A mail user is somewhat similar to Contact, but with an Active Directory logon account.  In Exchange Server 2003 this recipient was called a Mail-enabled User.

Mail contact
A mail contact contains information about people or organizations that exist outside your Exchange organization.  Each mail contact has an external e-mail address, for example, support@dell.com.  Such objects appear in the Global Address List (GAL), but have no logon account.  This recipient is also known as a Mail-enabled Contact.

Mail-enabled universal distribution group (DL)
This is the classic distribution list.  Create a mail-enabled Active Directory distribution group so that users can send messages to multiple recipients.  To learn more, launch the Exchange Management Console --> Recipient Configuration, seek the 'New Distribution Group Wizard'.

Potential confusion:  In Active Directory, a distribution group means that the object does not have a security context, therefore it has no associated Active Directory account.  In contrast, Exchange 2007, calls all mail-enabled groups distribution groups.  Exchange 2007 terminology does not differentiate between universal distribution groups with, or without, a security context.  Confused?  Just create a few objects, and the wizards will magically disolve your mist of bewilderment.

Mail-enabled universal security group
The keyword, and the key difference from the above recipient is - security.  A mail-enabled Active Directory security group object can be used to grant access permissions to resources in Active Directory, and can also be used to distribute messages.

Take care before you mail-enable a universal group.  Guy says these objects are designed to control permissions.  They obviously have a use, but to me they are disaster waiting to happen.

Dynamic distribution group
A dynamic distribution group uses recipient filters and conditions to derive its membership at the time messages are sent.  This an excellent type of distribution group, therefore, don't miss a chance to investigate and to deploy them rather than static groups.

This recipient type was (is) also known as a query-based distribution group.  One factor that makes this recipient even better is that senders must be authenticated in Exchange 2007.  The only downside is the performance hit placed on the Global Catalog server when determining dynamic group membership.

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Mail forest contact (Exotic and rare)
A mail contact that represents a recipient object from another forest.  Mail forest contacts are created by Microsoft Identity Integration Server (MIIS) synchronization.

Linked mailbox (Uncommon)
A mailbox that is assigned to an individual user in a separate, trusted forest.

Please note Mail forest contacts are read-only recipient objects that are updated only through MIIS.  You cannot modify a mail forest contact by using the Exchange Management Console or Shell.

Shared mailbox
A mailbox that is not primarily associated with a single user and is generally configured to allow logon access for multiple users.

Legacy mailbox
A mailbox that resides on a server running Exchange Server 2003 or Exchange 2000 Server.

Room mailbox (Resource object)
This is the classic resource mailbox which you assign to a meeting location, such as a conference center, or training room.  Users can include Room mailboxes as resources in meeting requests.

Equipment mailbox (Resource object)
A resource mailbox that is assigned to a non-location specific resource, such as a laptop, projector, or even a company car.  Equipment mailboxes can be included as resources in meeting requests, providing a simple and efficient way for users to use resources.

Mail-enabled public folder
An Exchange public folder that is configured to receive messages.

Microsoft Exchange Recipient
The Microsoft Exchange recipient is a special recipient object that provides a unified and well-known message sender that differentiates system-generated messages from other messages.  It replaces the 'System Administrator' sender that was used for system-generated messages in Exchange Server 2003.

Mail-enabled non-universal group (Phased out)
A mail-enabled Active Directory global or local group object.  Mail-enabled non-universal groups are de-emphasized in Exchange 2007 and can exist only if they were migrated from previous versions of Exchange. You cannot use Exchange 2007 to create new non-universal distribution groups.

Exchange Server 2007 is a complex topic, do you need practical hands on training?  As an MCT trainer, I can thoroughly recommend TrainSignal.  In particular, I like the way that TrainSignal cover all learning methods, instructor lead, video and of course text material.  You can either take one module, for example Exchange 2007 or go for a combination of modules.  Learn more about Microsoft Exchange Server 2007 here

Practical Tasks - How to create Exchange 2007 Recipients

The best way to understand Exchange 2007 recipients is to consult the 'Wizards' in the Exchange Management Console --> Recipient Configuration container.  By clicking through the menus, Microsoft's options and terminology begin to make sense.  When you focus on creating one recipient type all becomes clear, whereas if you just read about the myriad of recipient options, eventually a fog of confusion descends.

Once you have some experience of creating recipient objects with Wizards consider using PowerShell.  Trust me; PowerShell is the easiest scripting language for non programmers to learn enough to get by and create, enable and modify your Exchange 2007 recipients.  The benefit of PowerShell is speed, especially if you want to modify lots of recipients with one command.

Example of PowerShell adding Guy to a distribution group called Techies:
Add-DistributionGroupMember -Identity "Techies" -Member guy@cp.com

Do you think you could add a user called Fred to a distribution group called Managers.  I believe you could using PowerShell.

If the recipient object needs an account in Active Directory, then connect to a domain controller and use the ADUC.  This page will give you practical advice on how to create Exchange 2007 recipients.

Summary of Recipient Types in Exchange Server 2007

When it comes to understanding recipient types in Exchange 2007, ask yourself, does the object have an account in active directory?  And, where is the email stored?  To shortcut your learning seek out icons, they are so much more descriptive than the labels.

Also remember that with Exchange 2007, Microsoft have moved recipient tasks to the Exchange Management Console.  Thus if you are familiar with Exchange 2003, try and unlearn managing recipients via Active Directory Users and Computers, instead switch to the Exchange Management Console

See more Microsoft Exchange Server 2007 topics:

• Exchange 2007 Home   • SP1   • Migration   • Compatibility   • ExBPA   • Free Syslog Analyser

• Install   • Server Roles   • CAS Role   • Hub Transport  • SMTP Connector   • NDRs  • Exchange CCR

• Mailbox Role   • Create Mailbox   • Mailbox Stores   • Recipients   • OWA   • GAL   • Eseutil   • Edge

Please write in if you see errors of any kind.  Please report any factual mistakes, grammatical errors or broken links, I will be happy to not only to correct the fault, but also to give you credit.

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