Problem scenario
You have a VPC. You want a NACL to protect your VPC from hackers and other networks. What do you do?
Solution
Network ACLs are created by default when you create a VPC. They can be configured the same way Security Groups are configured in the AWS Console. Go to the VPC Dashboard -> Security -> Network ACLs. Click on the relevant Network ACL. Click either the "Inbound Rules" or the "Outbound Rules" and modify them accordingly to harden your VPC.