This network ACL is the recommended baseline for AWS VPC subnets. It should be configured and used on all AWS VPC subnets. You are welcome to make your NACL more stringent, but we recommend careful consideration before making it less stringent.
CloudFormation
A CloudFormation template to create a Network ACL for with the baseline rules can be found here: https://github.com/CU-CommunityApps/cu-aws-cloudformation/tree/master/baseline-nacl
Manual Configuration
Inbound Rules
Outbound Rules
