I deal with a number of more traditional/large financial firms and when they inevitably ask me what my public IP addresses are so that they can white list them on their firewall, I have to send them a large number of ranges covering various cloud services ... kind of renders the exercise pointless.
sth like this
aws ec2 describe-instances --query "Reservations[*].Instances[*].[PublicIpAddress]"
Listing out all your internet routable interfaces presumably to lock down the unintentional ones?
I did something similar here when I wanted all the internal hostnames I had to resolve locally via dnsmasq: