典型使用场景 单一公开子网 公开子网和私有子网 企业数据中心+公开子网 企业数据中心 公网网关 An Internet gateway is a fully managed AWS service that performs bi-direction source and destination network address translation for your EC2 instances. Optionally, a VPC may use a virtual private gateway to grant instances secure access to a user’s corporate network via VPN or direct connect links. Instances in a subnet can also be granted outbound only Internet access through a NAT gateway.