There are two aspects to calendar sharing in Exchange--sharing your calendar with other people, asking or having them share their calendar with you.
Sharing your calendar with others
*If you type 'net-ID@iastate.edu' instead of one of the options listed above, Exchange will think you're trying to share your calendar with an external account and will, rightly, say that you don't have permission to do so.
NOTE: The method listed above will allow the person you share your calendar with to view but not alter your calendar. If you want to give someone additional permissions (for example, permission to enter events in your calendar), right-click on 'Calendar' (under All Calendar Items). Select Permissions. Add the person's Net-ID. Select the appropriate Permissions level from the drop-down menu.
Other people sharing their calendar with you
Remember before you can view someone else's calendar, they have to grant you permission. If you can't view a calendar, first contact that person and make sure they have gone through the steps listed above.
...you will never receive an out-of-the-blue email from ISU Extension IT staff requesting your password.
Do not respond to email which does not identify a specific person or persons (but just says 'iastate.edu support team' or 'ISU Extension support team' or some other general label), particularly if they are requesting secure information like your password or Social Security Number. Do not respond to email that comes from a non-iastate.edu address, but claims to require your iastate.edu password.
Neither EIT or ISU IT will ever ask you for your password in an email. No other organization you do business with should ever ask you for your password via email either.
When you receive messages like this, you can trash them.