Question

What are AWS NACLs and Security Groups?

Answer 1

• AWS NACL (Network Access Control List):

  • Operates at the subnet level.
  • Stateful: Both inbound and outbound rules are evaluated.
  • Rules are ordered, and the highest priority rule that matches is applied (like firewall rules).
  • Can explicitly allow or deny traffic based on IP addresses, protocols, and ports.

• AWS Security Groups:

  • Operates at the instance level (EC2 instances, RDS instances, etc.).
  • Stateful: Inbound rules are automatically allowed outbound traffic for responses.
  • Rules are evaluated independently and allow traffic based on allow rules (implicit deny).
  • Can control traffic based on IP addresses, protocols, and ports.