When you are unable to check your mails regularly (i.e. you are on a business trip), Auto-Reply can be helpful as it automatically sends mail replies to your contacts to inform them of your absence.
(1) On the left menu, click Preferences, expand Mail Options , and select Auto-Reply.
(2) In the [Auto-Reply] page, check the Activate Auto-Reply box, enter your auto-reply content, and specify the auto-reply interval.
(3) Click OK when finished.
(4) To disable Auto-Reply, uncheck the Activate Auto-Reply box.