Security group architecture for AWS: How to overcome security group limits
As with all cloud vendors, AWS users share responsibility for securing their infrastructure against risk. Amazon provides the tools you need to filter traffic, but configuring those tools is up to you. Firewalls are one of the tools you’ll use to filter traffic and secure Virtual Private Cloud (VPC) instances. Instead of using traditional firewalls, Amazon provides users with AWS security groups, which are flexible, stateful firewalls capable of filtering inbound and outbound traffic.