IMSS implementing anti-spoofing measure

On Thursday, November 3 at 10:00AM, IMSS will be making some changes to the main campus email servers to reject incoming mail from off-campus sources where the sender is sending from an address without logging in (aka spoofing). Most legitimate Caltech mail users already log in when sending mail, so this should have little impact. Exceptions have also been made for authorized bulk email services that send mail in this way. By making this change, IMSS hopes to greatly reduce the number of scam messages in users' inboxes that use fake Caltech sender addresses. For questions, please contact the Help Desk (x3500,,