You have complete control over the visibility of your systems. You can choose whom the system is vissible and whom not.The Amazon EC2 security systems allow you to place your running instances into arbitrary groups of your choice. Using security groups can restrict the system to communicate with which other groups, and also which IP subnets on the Internet may talk to which groups. This allows you to control access to your instances in our highly dynamic environment. You can manage all the incoming and outgoing traffic to and from your instance by the help of security group and VPC and subnets. This way you can keep your EC2 instance private and away from the remaining world.