Create an API for maintaining the IP address and accessible URLs as same as Office 365 provided below;

https://docs.microsoft.com/en-us/office365/enterprise/urls-and-ip-address-ranges

This would allow the rules to be updated via a script.

Regarding Dynamics 365, IP address and URL information is published as Knowledge Base article. However, maintenance of firewall/proxy from this KB article is very cumbersome and hard to maintain.


https://support.microsoft.com/en-us/help/2728473/microsoft-dynamics-crm-online-ip-address-ranges


https://support.microsoft.com/en-us/help/2655102/internet-accessible-urls-required-for-connectivity-to-microsoft-dynami