Microsoft's Terry Zink announced yesterday on the Mailop list that Microsoft is combining the infrastructure for Outlook.com (Hotmail) and Office 365. As part of this infrastructure update, Microsoft is letting the world know that soon, all outlook.com (hotmail.*, live.*, msn.*, etc.) consumer email traffic will originate from IP addresses in the 220.127.116.11/14 (18.104.22.168 - 22.214.171.124) network range. Folks running spam filters will want to update their systems accordingly.