Your primary email address is xxxxxx@cs.stanford.edu where xxxxxx is your CSID, which is also your xenon username. You will also automatically have an equivalent email address of the form first.last@cs.stanford.edu, where "first" is your first name and "last" is your last name.
Login via https://cs.stanford.edu/pedit to specify where you want your CS email forwarded. You must have it forwarded somewhere or you won't receive any email sent to your CS account.
Your xenon .forward file doesn't do anything unless your CS mail forwards to your Xenon address. That is, your CS forwarding address takes precedence over your .forward file.
