...
If you wish, you can restrict the IP addresses used with Azure to restrict access to PICSWeb IP ranges only. To do this, open Azure, enter Storage Accounts into the search bar and select your storage account. In the navigation menu for your account, go to the Networking page and select Enabled from selected virtual networks and IP addresses from the Public network access menu.
The following addresses are required for PICSWeb to communicate with Azure:
31.28.78.36
31.28.78.37
146.101.18.36
146.101.18.37
After this, enter the required IP addresses into the Firewall section and select Save to finish.
...