A. Forwarding email is often necessary when users need to get their Microsoft Exchange Server mail from outside your network. For example, if your sales manager needs to check email while out of the office, he or she might want to use a Web-based email service to do it (e.g., Hotmail, AOL, or Mindspring).
If you want to send all copies of an employee's email to an external site, use the external SMTP address to create a custom recipient. On the mailbox's Delivery Options tab, designate the custom receipt as an alternate recipient. Also, be sure to check the Deliver messages to both recipient and alternate recipient checkbox.
If you want to send the email to the external recipient at an SMTP address on Exchange Server (for example, if you want email@example.com to forward mail to firstname.lastname@example.org without creating an information mailbox on the server), create a custom recipient and give it two SMTP addresses. The primary address must be the address you want the server to use to send the mail (email@example.com in this example). The secondary SMTP address is the address you want people to use (firstname.lastname@example.org). (If you need to set up alternate email boxes for several users, see "How to Set Up Batch Auto-forward Rules Using Exchange".)