For Exchange users:
In Outlookweb:
Click the gear in the upper right.
Click “options” at the bottom.
On the far left, click “organize email”.
If it’s not already on the “inbox rules” page, click “inbox rules” at the top.
Click the plus sign.
Click “Create new rule for arriving messages…”.
Enter a name for the rule. Something like “Redirect all messages”.
Click the first dropdown, then click “[Apply to all messages]” at the bottom.
Click the second dropdown and click “Redirect the message to…”
If it doesn’t automatically open a new window, click “*Select people…”
Click in the To field at the top, enter your external email address, and click “Use this address”.
Click OK at the top.
Click the “save” button.
Click “yes” to confirm that you want the rule to apply to all future messages.