Network Security Groups

Configures network security groups and firewall rules across AWS, GCP, and Kubernetes to control traffic flow and enforce network segmentation. You'll reach for this when setting up multi-tier applications, restricting database access, or implementing zero-trust networking. The reference guides cover Security Groups in AWS, Network Policies in Kubernetes, and GCP Firewall Rules with working YAML examples. The best practices section hammers home the important stuff: never expose databases to 0.0.0.0/0, document every rule's purpose, and use security group references instead of hardcoded IPs. It's comprehensive enough to get proper network isolation running without having to piece together documentation from three different cloud providers.

skills.sh installs: 446
GitHub stars: 379
last updated: Aug 21, 2026

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Install

$ npx -y skills add aj-geddes/useful-ai-prompts --skill network-security-groups --agent claude-code

Installs into .claude/skills of the current project.

Files

Overview

Implement network security groups and firewall rules to enforce least privilege access, segment networks, and protect infrastructure from unauthorized access.

When to Use

Inbound traffic control
Outbound traffic filtering
Network segmentation
Zero-trust networking
DDoS mitigation
Database access restriction
VPN access control
Multi-tier application security

Quick Start

Minimal working example:

# aws-security-groups.yaml
Resources:
  # VPC Security Group
  VPCSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: VPC security group
      VpcId: vpc-12345678
      SecurityGroupIngress:
        # Allow HTTP from anywhere
        - IpProtocol: tcp
          FromPort: 80
          ToPort: 80
          CidrIp: 0.0.0.0/0
          Description: "HTTP from anywhere"

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