Configuring X.400 Authoritative Domains
You configure an X.400 authoritative domain on the Hub Transport server role. When an organization is configured as authoritative for a particular domain, it is assumed that the organization hosts all the mailboxes for recipients in that domain. After you create an X.400 authoritative domain name, you can create an e-mail address policy that specifies that domain in the e-mail proxy address. The Exchange organization accepts e-mail that is addressed to recipients who have been assigned an X.400 e-mail proxy address that uses the X.400 authoritative domain namespace. Any X.400 recipient addresses in the authoritative namespace that do not resolve to a mailbox or a contact in the Active Directory directory service are treated as an error and cause messages to result in a non-delivery report (NDR). If the message that causes the error is a Delivery Status Notification (DSN), such as an NDR, it is deleted.
Exchange 2007 supports nonauthoritative X.400 domains if they are a subdomain of an authoritative domain. You use the X400ExternalRelay parameter of the New-X400AuthoritativeDomain cmdlet to define any exceptions where the Exchange organization is not authoritative for a subdomain of the authoritative X.400 domain. By default, the value of the X400ExternalRelay parameter is set to $false. Therefore, a recipient resolution failure for an e-mail that is sent to a recipient in the X.400 subdomain results in an NDR. If the value of the X400ExternalRelay parameter is set to $true, Exchange does not treat recipient resolution failures as an error and routes messages that are addressed to a recipient in the X.400 subdomain to an external address.
Defining an X.400 Namespace
By default, when you configure an X.400 authoritative domain, the Exchange organization is considered authoritative for all X.400 addresses in the hierarchy.
An X.400 address consists of a series of attributes that define organizational components and specify recipients. The X.400 namespace that is specified in the X400DomainName parameter can only include the X.400 organizational components. The following table lists the attributes that you can use to define an X.400 domain namespace in Exchange 2007 SP1. The attributes are listed in hierarchical order.
X.400 organizational components
|
Attribute abbreviation
|
Organizational component
|
Required/Optional
|
Maximum character length
|
|---|
|
C
|
Country The value of the Country attribute is the two-letter country/region designation from International Organization for Standardization (ISO) 3166. This attribute identifies the country or region of the X.400 domain namespace.
|
Required
|
2
|
|
A
|
ADMD The value of the Administration Management Domain (ADMD) typically identifies a public mail service provider. Valid values are decided on a country or regional basis.
|
Required
|
16
|
|
P
|
PRMD The value of the Private Management Domain (PRMD) defines the top level domain in the namespace of the Exchange organization.
|
Optional
|
16
|
|
O
|
Organization The value of the Organization is unique within the context of the PRMD or of the ADMD if there is no PRMD.
|
Optional
|
64
|
|
OU1
|
Organizational unit 1 The value of each organizational unit identifies a unique address element within the scope of the immediately superior address element in the hierarchy.
|
Optional
|
64
|
|
OU2
|
Organizational unit 2 The value of each organizational unit identifies a unique address element within the scope of the immediately superior address element in the hierarchy.
|
Optional
|
64
|
|
OU3
|
Organizational unit 3 The value of each organizational unit identifies a unique address element within the scope of the immediately superior address element in the hierarchy.
|
Optional
|
64
|
|
OU4
|
Organizational unit 4 The value of each organizational unit identifies a unique address element within the scope of the immediately superior address element in the hierarchy.
|
Optional
|
64
|
When you specify the X.400 namespace, the address attributes must be separated by semicolons and the address must be enclosed in quotation marks, as in the following example:
"C=US;A=ATT;P=Contoso;O=Example"
X.400 domain names can only include the following ASCII characters:
-
A to Z
-
a to z
-
0-9
-
These punctuation and special characters: (space)
' () + , - . / : = ?
The inclusion of a wildcard character, such as an asterisk ( * ), is not supported in the X.400 authoritative namespace. Each attribute can appear only one time in the X.400 namespace.
Any address in the hierarchy that is subordinate to the defined organizational components must resolve to a recipient or contact in Active Directory, unless an exception has been defined for a subdomain by specifying the X400ExternalRelay parameter as $true. If the categorizer cannot resolve a recipient, an NDR is generated for a message. If the message is a DSN, it is deleted.
For example, if you have configured an X.400 authoritative domain as "C= US;A=ATT;O=Contoso", the Exchange organization is also considered authoritative for the X.400 namespace "C=US;A=ATT;O=Contoso;OU1=Tailspin Toys". If all the recipients for Tailspin Toys are located in another organization, each of those recipients must be represented as a contact in the Active Directory of the Contoso organization. If you cannot do this, the Tailspin Toys namespace must be defined as an external relay subdomain.