AWS Certified Solutions Architect Associate Test 3

Amazon VPC provides two features that you can use to increase security for your VPC:
Security groups--Act as a firewall for associated Amazon EC2 instances, controlling both inbound and outbound traffic at the instance level and supports allow rules only. Network access control lists (ACLs)--Act as a firewall for associated subnets, controlling both inbound and outbound traffic at the subnet level and supports allow rules and deny rules.
Reference: http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Security.html