Defined in github.com/aws/aws-sdk-go/service/ec2/api.go
Indicates whether source/destination checking is enabled. A value of true means checking is enabled, and false means checking is disabled. This value must be false for a NAT instance to perform NAT. For more information, see NAT Instances (http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_NAT_Instance.html) in the Amazon Virtual Private Cloud User Guide.