Office 365 IP Address changes

Occasional Visitor



In order to allow Office365 Exchange IPs in a firewall, i'd like to use Microsoft's API stated in this page:

Specifically using id 9 and 10.


My questions are:

1. Is this page/API mentioned in it( consistent?

2. Are there pre-defined periods of time that these IPs/CIDRs change?


For example, if Microsoft will decide to add/remove an IP/IP range from mentioned above URL, can I be sure that there will not be a gap of time since the actual IP change and an update of that page?


Thank you in advance.

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