Issue
If blanket allowance for “*.amazonaws.com” cannot be provided for AWS Cloud Discovery, List of exact URL endpoints need to be whitelisted to run the AWS Cloud Discovery.
Resolution
Use the list in below AWS documentation for service endpoints:
https://docs.aws.amazon.com/general/latest/gr/ec2-service.html
Refer to the attached file "aws-general.pdf" (downloaded from https://docs.aws.amazon.com/general/latest/gr/rande.html) for the same information at page 125.
There's one more URL to add:
https://ec2.amazonaws.com
This should cover the URLs that AWS cloud discovery need.
Related Links
Amazon Documentation:
https://docs.aws.amazon.com/general/latest/gr/rande.html
https://docs.aws.amazon.com/general/latest/gr/aws-service-information.html
https://docs.aws.amazon.com/general/latest/gr/ec2-service.html