I was starting a neptune database from this base stack
https://s3.amazonaws.com/aws-neptune-customer-samples/v2/cloudformation-templates/neptune-base-stack.json
However now i am wondering why a NAT Gateway and also an Internet Gateway are started in this stack? are they required for updates within Neptune? This seems like a huge security risk.
On top of that these gateways are not cheap.
I would be happy for an explanation on this