Security Groups

The fundamental of network security in AWS

• Can be attached to multiple instances
• Locked down to a region / VPC combination
• Does live “outside” the EC2 - if traffic is blocked, the EC2 instance won’t see it
• It’s good to maintain one separate security group for SSH access
• If your application is not accessible (time out), then it’s usually a security group issue
• If your application gives a “connection refused” error, then it’s an application error or its not launched
• All inbound traffic is blocked by default
• All outbound traffic authorized by default

Security groups act as a firewall on EC2 Instances

• They regulate:
  • Access to ports
  • Authorized IP ranges - IPv4 and IPv6
  • Control of inbound network
  • Control of outbound network