I have several mailboxes I log into on an occasional basis. Since I am not logged in continuously and none of those are my primary mailbox, the normal auto-reply rule will not work. I had to set up a server-based rule to run any time a message is sent, regardless of whether I was in the box or not.
And here's how to set it up:
1. Log into the mailbox in which you need the rule.
2. Click Tools menu
3. Select Rules and Alerts
4. Select New Rule
5. Select Start from a blank rule
6. Click Check messages when they arrive
7. Click Next
8. Under Which conditions do you want to check, select Sent only to me (or you can choose any ones which apply to your needs)
9. Click Next
10. Select Have server reply using specific message
11. Click Specific Message link in the Step 2 window below
12. It will open a mail message dialog box which you can populate as needed. Save it.
13. Click Next
14. Check any exceptions you might have (such as specific groups/persons). Click Next when done.
15. Enter Name for Rule and check Turn on Rule
16. Click Finish to save
Now your rule will run off the server and not just when you are logged into that mailbox.