First result on Google: https://docs.microsoft.com/en-ca/office365/enterprise/urls-and-ip-address-ranges?redirectSourcePath=%252farticle%252fOffice-365-URLs-and-IP-address-ranges-8548a211-3fe7-47cb-abb1-355ea5aa88a2

On Sep 25 2018, at 12:13 pm, David Bass <davidbass570@gmail.com> wrote:

Does anyone have a good list of all of the US IPs used for O365?  Not looking for specific IPs, and can just use the blocks. 

Thanks!