CCNA Configuring Access and Security Questions

Private Google Access on the subnet is the correct configuration to enable VMs without external IPs to reach Google APIs and services. When enabled, the subnet's VMs can send traffic to Google's public API IPs, which are then routed internally through the VPC's default route and into Google's network without ever needing an external IP. This is a subnet-level Boolean flag that must be turned on for each subnet where you want the capability; it applies to the entire subnet and works with the standard default route. Enabling this is the direct, documented mechanism that satisfies the security engineer's requirement.

Rule B has a priority of 500, which is numerically lower than Rule A's priority of 1000, so GCP evaluates Rule B first. Because Rule B's action is to deny and the traffic matches its conditions, that denial is the final decision. Rule A is not evaluated, so the traffic is denied as expected.

Cloud NAT enables outbound internet access for private instances.

Cloud NAT, configured through a Cloud Router, provides managed outbound internet connectivity to private Compute Engine instances without assigning them external IP addresses. It uses the Cloud Router to dynamically exchange routing information with the VPC network, allowing instances with internal IPs to initiate connections to the internet while remaining unreachable from outside. This is the recommended, highly available, and serverless solution because Cloud NAT automatically scales to handle thousands of instances and does not require manual patching or failover configuration.

Attaching the service account to the Compute Engine instance at creation time is necessary for the instance to inherit the service account's IAM permissions. When an instance runs with an attached service account, the metadata server provides OAuth tokens for client libraries and tools like gcloud to access Cloud APIs automatically. Without this attachment, the instance has no identity to use for authenticating API calls, so the service account's permissions would never apply.

Granting the roles/secretmanager.secretAccessor role to the Compute Engine default service account is the correct approach because it gives the instance's identity the minimum permission needed to access secret versions. The instance authenticates through the metadata server, so no long-lived keys are stored on the instance. This makes it the most secure and operationally simple method, and it aligns with Google's recommended practice of using IAM roles on service accounts rather than embedding credentials.

This command correctly creates a Google-managed SSL certificate for the domain 'example.com'. The --domains flag tells the Cloud API to request a managed certificate, which Google will automatically obtain and renew without requiring you to upload a private key. Note that for a global external load balancer, you should also include --global, but the essential syntax for a managed certificate is exactly this.

Attaching the service account via the --service-account flag at instance creation is the correct approach because it binds the identity to the VM and makes credentials available through the metadata server. Code running on the instance can fetch OAuth 2.0 tokens from the metadata endpoint (http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/token) and act on behalf of the service account. This avoids managing key files and ensures that IAM permissions are automatically applied to the instance.