Problem

What are the IP Addresses used by Microsoft Office 365?

Solution

We are often asked what IP Addresses does Microsoft Office 365 use for their end-points?

This is especially useful when running a hybrid solution with Office365 and on-premise Exchange, or other 3rd party solutions, and you want to lock down access with firewall rules.

Microsoft have published an article on this called "Office 365 IP Address and URL web service"

However is thats too long to read.

<TL;DR>

The link to the published IP Addresses can be found here ->  https://endpoints.office.com/endpoints/worldwide?clientrequestid=b10c5ed1-bad1-445f-b386-b919946339a7