The Addr-Type object specifies a type of foreign system for which the Microsoft Exchange Server can create a proxy address. You must have an address type for each type of foreign system where the server sends messages. There is a one-to-one relationship between address types and address templates.
For example, SMTP (Internet) business addresses take the form of user@domain.com, where user is the account name of the user and domain is the name of the host computer domain.
Because Addr-Type objects appear to MAPI as messaging user objects, use the MAPI IMailUser interface to access an Addr-Type object.
To determine whether an address type already exists, call the HrAddressTypeExists function. To install an address type, call the HrInstallAddressType function. To remove an address type, call the HrRemoveAddressType function.