When you create an internal Elastic Load Balancer in a VPC, you need to select private subnets thatare in the same Availability Zone as your instances. If the VPC Elastic Load Balancer is to be publicfacing, you need to create the Elastic Load Balancer in a public subnet. A subnet is a public subnet if itis attached to an Internet Gateway (IGW) with a defined route to that gateway.Selecting more than one public subnet increases the availability of your Elastic Load Balancer. NBElasticLoad Balancers in EC2-Classic are always Internet-facing load balancers. Reference: http://docs.aws.amazon.com/ElasticLoadBalancing/latest/DeveloperGuide/elb-internetfacing-load-balancers.html