Microsoft Exchange Server 2010 : Defining Email Addresses (part 1) - Accepted Domains

Before we discuss how to create mail-enabled users, groups, or contacts, we'll first discuss how these objects get their email addresses. Those of you who are familiar with Exchange 2000/2003 probably remember that email addresses were defined by a recipient policy. Once the recipient policy was defined, the Microsoft Exchange System Attendant's Recipient Update Service (RUS) would establish email addresses for any mail-enabled recipient at some point in the future (hopefully just a minute or two).

This process is just a bit different in Exchange 2007 and Exchange 2010. Email addresses are generated for the object at the time the mail-enabled recipient is created, and they are generated by an Exchange Management Shell (EMS) task or the Exchange Management Console (EMC)—still with a background EMS task, though. Recipient policies from Exchange 2000/2003 have been broken up into two separate concepts:

• Email domains for which your organization will accept mail

• Email address policies for your users

For addresses that will be assigned to mailboxes on your Exchange 2010 servers, you define both an accepted domain and an email address policy.

1. Accepted Domains

An accepted domain is an SMTP domain name (aka SMTP namespace) for which your Exchange 2010 servers will accept mail. The servers will either deliver the mail to Exchange 2010 mailboxes or relay it on to internal or external SMTP mail servers. If you are in the middle of a migration from Exchange 2000/2003, the accepted domains list will include the SMTP domains for your Exchange 2000/2003 mailboxes. Accepted domains must be defined for all email addresses that will be routed into your organization by your Hub Transport servers.

Most small and medium-sized organizations will have only a single accepted domain.

1.1. Setting Up an Accepted Domain Using the EMC

Accepted domains are found within the Organization Configuration work center under the Hub Transport subcontainer. When you choose the Accepted Domains tab in the Results pane, you will see a list of the accepted domains that have been defined for your organization, such as those shown in Figure 1.

Figure 1. List of accepted domains

When you create an Exchange organization, a single accepted domain is automatically created and given a name. This is the name of the Active Directory forest root domain; for many organizations this will not be correct because the naming convention for Active Directory domain names and SMTP domain names may be different. For example, your Active Directory name may be Netlogon.local whereas your public domain name for email is Netlogon.com.

Accepted domains are simple to create and require little input. To create a new accepted domain using the EMC, click the New Accepted Domain task in the Actions pane to launch the New Accepted Domain Wizard (shown in Figure 2). You only need to provide a descriptive name for the accepted domain, the SMTP domain name, and how messages for this domain should be treated when messages are accepted by Exchange 2010.

Keep in mind that you cannot change the domain name of an accepted domain once it is created. (You can change the domain type, however.)

1.2. Setting Up an Accepted Domain Using the EMS

You can also manage accepted domains using the following EMS cmdlets:

• New-AcceptedDomain

• Set-AcceptedDomain

• Get-AcceptedDomain

• Remove-AcceptedDomain

Figure 2. Creating a new accepted domain

For example, to create a new accepted domain for a Canadian division of Leigh Enterprises, use the following EMS command:

New-AcceptedDomain -Name "Leigh Enterprises Canada" -DomainName "leigh-inc.ca"

-DomainType "Authoritative"

					  

1.2.1. About Domain Types

One tricky thing about defining an accepted domain is that you must define how Exchange is to treat a message for it. You can choose from three types of domains when creating an accepted domain:

Authoritative Domains

These are SMTP domains for which you accept the inbound message and deliver it to an internal mailbox within your Exchange organization.

Internal Relay Domains

These are SMTP domains for which your Exchange server will accept inbound SMTP mail. The Exchange server must have mail-enabled contacts or mail-enabled users who specify forwarding addresses for users in those domains. The Exchange server then relays the message on to another internal mail system. Internal relay domains are used when two Exchange organizations are doing global address list synchronization.

External Relay Domains

These are SMTP domains for which your Exchange organization will accept inbound SMTP mail and then relay that mail on to an external SMTP mail server, usually one that is outside of the organization's boundaries. If Edge Transport servers are used, the Edge Transport server handles external relay domains.