Security groups
Availability Zones
Network ACLs
Geo Redundant Servers
Explanations:
Security groups in VPC are stateful, meaning return traffic is automatically allowed, regardless of the inbound or outbound rules. If an instance sends a request, the corresponding response is automatically allowed even if no specific inbound rule exists for it.
Availability Zones are physical locations within a region and are not related to network traffic rules. They do not manage stateful or stateless behaviors.
Network ACLs are stateless, meaning return traffic must be explicitly allowed by rules. Unlike security groups, ACLs do not automatically allow return traffic.
Geo-Redundant Servers refer to a design where servers are replicated across different geographic locations for redundancy and availability, unrelated to network traffic management.