How do you set up network segmentation and firewall rules with IaC?

IaC (Infrastructure as Code) uses code to automatically configure networks, where network segmentation isolates logical areas (such as subnets) and firewall rules control traffic access. Its importance lies in ensuring consistent security, the principle of least privilege, and repeatable deployment. It is applied in cloud environments (such as AWS VPC, Kubernetes clusters) to defend against lateral threats.

Core components include IaC tools (such as Terraform to define VPCs and subnets), segmentation policies (isolation based on tags or regions), and rules (such as security groups restricting ports/IPs). Principle: Code version control enables automated changes. Practical application: Isolating microservices or database layers through modular design to reduce configuration drift and enhance security compliance.

Implementation steps: 1. Select tools (e.g., Terraform). 2. Define segmentation (e.g.,划分公有/私有子网). 3. Configure rules (specify inbound/outbound allow lists). 4. Test and deploy (integrate CI/CD pipelines). Typical scenario: Isolating the production environment, only authorizing developer IP access. Business value: Accelerating deployment cycles, reducing the cost of human errors, and strengthening security posture.