I would like to open firewall rules for Microsoft LUIS. I have the port number, but I'm unable to find the IP ranges it uses.
The answer would depend on your app's deployment region, and keep in mind, the IP range could change without notice.
You can find a list of Microsoft Azure datacenter IP ranges here:
This file contains the IP address ranges (including Compute, SQL and Storage ranges) used in the Microsoft Azure Datacenters. An updated file is posted weekly which reflects the currently deployed ranges and any upcoming changes to the IP ranges. New ranges appearing in the file will not be used in the datacenters for at least one week. Please download the new xml file every week and perform the necessary changes on your site to correctly identify services running in Azure. Express Route users may note this file used to update the BGP advertisement of Azure space in the first week of each month.
Note: These IP ranges change every week so whitelisting by Azure IP is at your own risk.