AWS Private EC2 Operations Guide Part 3: Connecting Without Bastion via SSM Session Manager — IAM Role, VPC Endpoint, and Port Forwarding
How to land a shell on a Private EC2 without ever opening port 22. The mechanics of SSM Session Manager (the agent polls AWS), the three prerequisites (Agent / IAM / network path), the cost trade-off between NAT Gateway and VPC Endpoints, and the port-forwarding pattern that securely reaches RDS without a VPN.