A common question among Microsoft Exchange Server administrators is, "How do we use Exchange Administrator to add multiple SMTP addresses?" The answer is, "You can't." The trick is to modify an object's Secondary-Proxy-Addresses property. This solution might not seem obvious, but Exchange Server stashes proxy addresses in this attribute.

Suppose you're BigCorp's Exchange Server administrator, and you're setting up a mailbox for Joan Smith. You've set up autonaming so that Joan's SMTP address will be joan.smith@bigcorp.com. Because you know that exact naming details are difficult to remember, you also want to let Joan get mail at jsmith@bigcorp.com and smith.joan@bigcorp.com. In a Comma Separated Values (CSV) file for Joan's mailbox, add the Secondary-Proxy-Addresses header property and appropriate values, as follows:

Obj-Class,Mode,Directory Name,Secondary-Proxy-Addresses

Mailbox,modify,Joan Smith,smtp:smith.joan@bigcorp.com%smtp:
jsmith@bigcorp.com

Notice that in the content line, SMTP is lowercase because these addresses aren't usable as reply addresses. Microsoft Exchange Administrator displays such an address in lowercase roman type.

Suppose you want to make this change for all users on the server. You can easily complete this task.

  1. From the Exchange Administrator Tools menu, click Directory Export to export all mailboxes. You can use the default header.
  2. Open the .csv file in Microsoft Excel and add a column named Secondary-Proxy-Addresses.
  3. Fill in the appropriate value or values for the secondary address or addresses. (Remember that you can supply multiple addresses by separating them with the percent sign character—%.) Now is a good time to brush up on your scripting skills so that you can write an Excel macro to rewrite existing SMTP addresses to the desired format.
  4. Save the .csv file.
  5. From the Exchange Administrator Tools menu, click Directory Import to import the .csv file. Because the default mode is modify, Exchange Administrator automatically loads the changes into the directory, and your work is finished.