For Office 365 customers who have restrictive firewalls for their employees it is important to have the right URLs or IP Addresses configured for uninterrupted access to Office 365. We have published this information on the TechNet page Office 365 URLs and IP address ranges. We have an RSS feed so that you can stay up to date with changes to this page. Some third-party companies provide applications that enable you to get email notifications of these changes. For example, one such third-party company is IFTTT Inc., and there is already an IFTTT recipe to do that (IFTTT account required). Here’s what an email from that might look like.