E-mail forwarding services

I am an e-mail administrator for a small liberal arts college. Our director of Alumni wants to offer lifetime e-mail for the Alum through some sort of forwarding software or service. I have only been able to find one service that looked promising and haven’t found any software that we can host. They don’t want us to mantain a mailbox for them so all they really want is for them to receive mail at @alumni.ourschool.edu.

If you have any suggestions please let me know.