A security group is a cloud traffic control construct that defines which inbound or outbound connections are allowed for attached resources.
A security group is a cloud traffic control construct that defines which inbound or outbound connections are allowed for attached resources. In plain language, it is a cloud-native way to restrict which network communication a workload should accept or initiate.
Security groups matter because cloud environments need local traffic controls around workloads and services. Without them, resources may end up much more reachable than intended.
They also matter because cloud networking changes quickly. Security groups help organizations enforce workload-level traffic policy in environments where instances and services may appear or change frequently.
Security groups appear in cloud virtual networks, instance deployment, platform hardening, and cloud posture review. Teams connect them to Virtual Private Cloud, Network Segmentation, Cloud Security Posture Management, and Cloud Workload Protection because traffic controls are a major part of cloud exposure management.
Security teams review security groups constantly for least-exposure, service reachability, and whether administrative or public access is broader than necessary.
A cloud-hosted application server needs to receive HTTPS traffic from the internet but should accept management traffic only from a controlled administrative path. The resource’s security group can express those rules directly around the workload.
A security group is not exactly the same as a traditional Firewall, even though it serves a similar traffic-control purpose. It is a cloud-native control attached to resources within the cloud provider’s networking model.
It is also different from a Virtual Private Cloud. A VPC defines a broader isolated cloud-network environment, while a security group applies traffic rules to attached resources inside or across that environment.