Security Groups vs NACLs Explained for Beginners In the previous articles, we learned about: VPC Subnets Internet Gateway Route Tables These components help AWS resources communicate with each other and with the internet. But there is still one important question: Even if a server is reachable, should everyone be allowed to access it? The answer is No . We need security controls that decide: Who can access our resources Which traffic is allowed Which traffic should be blocked AWS provides two im