Proxy Addresses

Topic Last Modified: 2007-11-09

A proxy address is the address by which a Microsoft Exchange Server 2007 recipient object is recognized in a foreign messaging system. Proxy addresses are required not only for users, but for all recipient objects, such as contacts, distribution groups, and public folders.

Each Exchange recipient object will have several proxy addresses — at least one for each foreign address type that is known to the system. The proxy addresses for each foreign address type are created by a DLL. You specify the location of this DLL as an attribute of the Addr-Type object when you install the address type in the Active Directory directory service.

The following table lists two proxy addresses that are associated with the Exchange 2007 user Jonathan Mollerup. Each proxy address is prefixed with its address type. The native transport for Exchange is now Simple Mail Transfer Protocol (SMTP). E-mail that originates in a foreign messaging system is addressed to Exchange 2007 recipients with proxy addresses that correspond to the foreign system.

Proxy addresses for Jonathan Mollerup

Users can have primary and secondary proxy addresses. The primary proxy address for a user is the one that is used to send e-mail to the foreign system. The secondary proxy addresses are used when e-mail is received from the foreign system. On outgoing messages, the primary proxy address is used as the address of the sender. On incoming messages, the recipient listed in the message is matched against the secondary proxy addresses in Active Directory to find the correct recipient object for the message.

A user has only one primary proxy address but might have multiple secondary proxy addresses. For example, if two companies merge and give new e-mail addresses to all the employees, the company might use secondary proxy addresses so that employees can receive e-mail at both their original and new e-mail addresses. By maintaining the old e-mail addresses as secondary proxy addresses, incoming e-mail can be addressed to either the original or new address. Outgoing e-mail is always sent from the primary proxy address.

A gateway should be able to generate proxy addresses for the following types of recipient objects:

• Users
• Contacts
• Groups
• Public folders

The gateway does not have to generate proxy addresses for one-off addresses.

For more information about proxy addresses and proxy address generation, see the following topics:

• Creating a Proxy Address
• Recipient Policies
• Address List Service