Who even can be sure microsoftonline.com is legit. Microsoft's domain story is such a mess, I wouldn't be surprised if not even internally they have one complete list of all the domain assets they own.
But they are not alone. It is kind of ironic when companies insist that we check the domain to spot spam but are unable publish a list with all domains they officially use to send mail.
But they are not alone. It is kind of ironic when companies insist that we check the domain to spot spam but are unable publish a list with all domains they officially use to send mail.