An accepted domain is any SMTP namespace for which an Exchange organization sends or receives e-mail. Accepted
domains include domains for which the Exchange organization is
authoritative, as well as domains for which the Exchange organization
relays mail.
Understanding Accepted Domains, Authoritative Domains, and Relay Domains
An organization can have more than one SMTP domain. The set of
e-mail domains your organization uses are its authoritative domains. An
accepted domain is considered authoritative when the Exchange
organization hosts mailboxes for recipients in this SMTP domain.
Transport servers should always accept e-mail that is addressed to any
of the organization's authoritative domains. By default, when you
install the first Hub Transport server, one accepted domain is
configured as authoritative for the Exchange organization, and this
default accepted domain is based on the FQDN of your forest root domain.
In many cases, an organization's internal domain name might differ
from its external domain name. You must create an accepted domain to
match your external domain name. You must also create an e-mail address
policy that assigns your external domain name to user e-mail addresses.
For example, your internal domain name might be cpandl.local, while
your external domain name is cpandl.com. When you configure DNS, the
DNS MX records for your organization will reference cpandl.com, and you
will want to assign this SMTP namespace to users by creating an e-mail
address policy.
When e-mail is received from the Internet by a Transport server and
the recipient of the message is not a part of your organization's
authoritative domains, the sending server is trying to relay messages
through your Transport servers. To prevent abuse of your servers,
Transport servers reject all e-mail that is not addressed to a
recipient in your organization's authoritative domains. However, at
times you might need to relay e-mail from another domain, such as
e-mail from a partner or subsidiary. In this case, you can configure
accepted domains as relay domains. When your Transport servers receive
the e-mail for a configured relay domain, they will relay the messages
to an e-mail server in that domain.
You can configure a relay domain as an internal relay domain or as
an external relay domain. You configure an internal relay domain when
there are contacts from the relay domain in the global address list. If
your organization contains more than one forest and has configured
global address list synchronization, the SMTP domain for one forest can
be configured as an internal relay domain in a second forest. Messages
from the Internet that are addressed to recipients in internal relay
domains are received and processed by your Edge Transport servers. They
are then relayed to your Hub Transport servers, which, in turn, route
the messages to the Hub Transport servers in the recipient forest.
Configuring an SMTP domain as an internal relay domain ensures that all
e-mail addressed to the relay domain is accepted by your Exchange
organization.
You configure an external relay domain when you want to relay
messages to an e-mail server that is both outside your Exchange
organization and outside the boundaries of your organization's network
perimeter. For this configuration to work, your DNS servers must have
an MX record for the external relay domain that references a public IP
address for the relaying Exchange organization. When your Edge
Transport servers receive the messages for recipients in the external
relay domain, they route the messages to the mail server for the
external relay domain. You must also configure a Send connector from
the Edge Transport server to the external relay domain. The external
relay domain can also be using your organization's Edge Transport
server as a smart host for outgoing mail.
You can view the accepted domains configured for your organization by completing the following steps:
-
In the Exchange Management Console, expand the Organization Configuration node, and then select the Hub Transport node.
-
On the Accepted Domains tab, accepted domains are listed by name,
SMTP domain name, and domain type. The domain type is listed as
Authoritative, External Relay, or Internal Relay as shown in Figure 1.
You can use the Get-AcceptedDomain cmdlet to list accepted
domains or to get information on a particular accepted domain as well.
If you do not provide an identity with this cmdlet, configuration
information for all accepted domains is displayed. Example 1 provides the syntax and usage, as well as sample output, for the Get-AcceptedDomain cmdlet.
Example 1. Get-AcceptedDomain cmdlet syntax and usage
Syntax
Get-AcceptedDomain [-Identity DomainIdentity]
[-DomainController DCName] [-Organization OrganizationId]
Usage
Get-AcceptedDomain -Identity "cpandl.com"
Output
Name DomainName DomainType Default
---- ---------- ---------- -------
cpandl cpandl.com Authoritative True
cohowinery *.cohowinery.com ExternalRelay False
