Exchange Server Addresses

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Exchange Server Addresses

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Microsoft® Exchange Server 2003 uses SMTP as its native transport, and primarily uses SMTP addresses when delivering messages.

However, MAPI clients, such as Microsoft Outlook®, still submit messages to the server using addresses that are based on Legacy (Exchange Server 5.5) distinguished names (DNs). Microsoft maintains an attribute, legacyExchangeDN, for every User object in Microsoft Active Directory®. The legacyExchangeDN attribute contains the DN of a user as it appears in Exchange 5.5. EX is the address type that was used for native Exchange Server addresses in earlier versions of Exchange. The unique address for each object in the original Exchange Directory was the DN of the object.

The Legacy DN begins with the Exchange Server domain at the highest level and continues to the object being named. The following table compares the Legacy DN and the valid Exchange addresses of a user named Jonathan Mollerup:

Legacy DN /o=HumongousInsurance/ou=New York/cn=Recipients/cn=JonM
Outlook address (built on Legacy DN) EX:/o=HumongousInsurance/ou=New York/cn=Recipients/cn=JonM
SMTP address SMTP:jonm@HumongousInsurance.com

It is important to note that:

  • After an Outlook message is submitted to the server, Exchange converts the EX:Legacy DN address to an SMTP address.
  • When a message arrives for a local recipient in the receiving Exchange server, Exchange first searches for the SMTP address of the recipient.
  • Active Directory also assigns a DN to objects. This is not the same as the Legacy DN. DNs in Active Directory are based on the LDAP naming convention and are one way that Active Directory references objects.
  • Exchange does not use Active Directory DNs for any sort of message transport. Exchange uses proxy addresses, Legacy DNs, and the X.400 address (if the X.400 address is configured).

An example of a distinguished name in Active Directory for Jonathan Mollerup would be:

CN=JonM, CN=Users, OU=New York, DC=HumongousInsurance, DC=com

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This topic last updated: March 2006

Build: June 2007 (2007.618.1)

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