Overview
Egress refers to the outbound flow of data from a private network (like a VPC or a Kubernetes cluster) to the public internet or another external network. Managing egress is critical for security and compliance.
Key Concepts
- Egress Rules: Policies that define which outbound connections are allowed (e.g., allowing a Pod to connect to an external database but blocking all other internet access).
- NAT Gateway: Often used to allow resources in a private subnet to initiate outbound traffic while preventing the internet from initiating connections to them.
- Service Mesh Egress: Tools like Istio can control and monitor all outbound traffic from microservices.
Importance
Controlling egress helps prevent data exfiltration and ensures that compromised systems cannot communicate with command-and-control servers.