Amazon ANS-C01 Practice Test - Questions Answers, Page 11

The correct approach is to use AWS Systems Manager Session Manager, which allows you to manage your EC2 instances through a secure and browser-based interface. By deploying and configuring SSM Agent on each instance, you can enable Session Manager to communicate with the instances. By deploying VPC endpoints for Session Manager, you can enable the instances to connect to the AWS service without requiring an internet gateway, NAT device, or VPN connection. You can also use IAM policies and SSM documents to implement role-based access control for managing the instances. This approach has the least maintenance overhead, as it does not require any additional infrastructure or configuration.

The correct answer is B. In each Availability Zone in the VPC, create a subnet that uses part of the allowed IP address range. Create a private NAT gateway in each of the new subnets. Update the route tables that are associated with other subnets to route application traffic to the private NAT gateway in the corresponding Availability Zone. Add a route to the route table that is associated with the subnets of the private NAT gateways to send traffic destined for the application to the transit gateway.

This solution meets the requirements because:

* It uses a private NAT gateway, which can route traffic to other VPCs or on-premises networks through a transit gateway or a virtual private gateway1.

* It creates a subnet in each Availability Zone that uses part of the approved IP address range, which ensures high availability and compliance.

* It updates the route tables to send traffic from the other subnets to the private NAT gateway in the same Availability Zone, which reduces latency and improves performance.

* It adds a route to the route table of the private NAT gateway subnets to send traffic destined for the application to the transit gateway, which enables connectivity to the on-premises network.

The other options are incorrect because:

* Option A uses a public NAT gateway, which is not necessary for connecting to other VPCs or on-premises networks. A public NAT gateway also requires an elastic IP address, which is not part of the approved IP address range.

* Option C creates only one subnet and one private NAT gateway, which does not provide high availability across multiple Availability Zones.

* Option D uses a public NAT gateway, which is not necessary for connecting to other VPCs or on-premises networks. A public NAT gateway also requires an elastic IP address, which is not part of the approved IP address range. Additionally, option D creates only one subnet and one public NAT gateway, which does not provide high availability across multiple Availability Zones.

The correct solution is to use a Route 53 private hosted zone and a Route 53 Resolver inbound endpoint. A private hosted zone allows you to use private domain names for your internal AWS resources without exposing them to the internet. A Route 53 Resolver inbound endpoint enables DNS queries from your on-premises network to be forwarded to your VPC. By configuring conditional forwarding on your on-premises DNS resolvers, you can ensure that only the queries for the AWS reserved domain name are sent to the inbound endpoint. In the private hosted zone, you can create primary and failover records that point to the IP addresses of the EC2 instances. These records will automatically switch to the failover instance if the primary instance becomes unhealthy. You can use CloudWatch metrics and alarms to monitor the application's health and trigger the health check for the primary endpoint.

The other options are not correct because they either expose the application to the internet or use a public hosted zone, which is not suitable for internal applications. Option A assigns public IP addresses to the EC2 instances, which makes them accessible from the internet. Option B uses a public hosted zone, which requires the EC2 instances to have public IP addresses or elastic IP addresses. Option D does not set up a health check on the alarm for the primary endpoint, which is required for the failover mechanism to work.

The correct answer is A, C, and D. These steps will meet the requirements with the least operational overhead because:

* Step A will deploy an AWS Lambda function to the shared services account that can automate the network infrastructure provisioning in each member account by assuming a role with the necessary permissions.

* Step C will create an AWS CloudFormation template that describes the VPC and the transit gateway attachment for each account. This template can be uploaded as an AWS Service Catalog product to the shared services account, which can be used by the AWS Lambda function to create the network resources in each member account.

* Step D will deploy an Amazon EventBridge rule on a default event bus in the shared services account that can react to AWS Control Tower lifecycle events, such as creating a new managed account. This rule can invoke the AWS Lambda function to provision the network infrastructure in the new account.

The other steps are incorrect because:

* Step B will update the existing accounts with an Account Factory Customization (AFC), which is a feature of AWS Control Tower that allows you to customize the account creation process with AWS CloudFormation templates. However, this step will not automate the network infrastructure provisioning for the existing accounts, as it only applies to the new accounts created through the Account Factory. Moreover, this step will require additional operational overhead to maintain the AFC templates and products.

* Step E will create an AWSControlTowerBlueprintAccess role in the shared services account, which is a role that allows AWS Control Tower to access the AWS Service Catalog products in the shared services account. However, this step is not necessary for the automation solution, as the AWS Lambda function can access the AWS Service Catalog products directly without using this role.

* Step F will create an AWSControlTowerBlueprintAccess role in each member account, which is a role that allows AWS Control Tower to access the AWS Service Catalog products in the member accounts. However, this step is not necessary for the automation solution, as the AWS Lambda function can access the AWS Service Catalog products in the shared services account without using this role.

A company ran out of IP address space in one of the Availability Zones in an AWS Region that the company uses. The Availability Zone that is out of space is assigned the

10.10.1.0/24 CIDR block. The company manages its networking configurations in an AWS CloudFormation stack. The company's VPC is assigned the 10.10.0.0/16 CIDR

block and has available capacity in the 10.10.1.0/22 CIDR block.

How should a network specialist add more IP address space in the existing VPC with the LEAST operational overhead?

A) Update the AWS :: EC2 :: Subnet resource for the Availability Zone in the CloudFormation stack. Change the CidrBlock property to 10.10.1.0/22.

B) Update the AWS :: EC2 :: VPC resource in the CloudFormation stack. Change the CidrBlock property to 10.10.1.0/22.

C) Copy the CloudFormation stack. Set the AWS :: EC2 :: VPC resource CidrBlock property to 10.10.0.0/16. Set the AWS :: EC2 :: Subnet resource CidrBlock property to 10.10.1.0/22 for the Availability Zone.

D) Create a new AWS :: EC2 :: Subnet resource for the Availability Zone in the CloudFormation stack. Set the CidrBlock property to 10.10.2.0/24.

To connect to multiple VPCs across different Regions using Direct Connect, the best option is to use a Direct Connect gateway and transit gateways. A Direct Connect gateway allows you to associate multiple virtual private gateways and transit gateways with the same Direct Connect connection. A transit gateway acts as a network hub that connects multiple VPCs and on-premises networks. By creating inter-Region peering connections between the transit gateways, you can enable cross-Region communication. Therefore, the steps are:

* Create four virtual private gateways and attach them to the four VPCs that need access from the on-premises location.

* Create a Direct Connect gateway and associate it with the four virtual private gateways.

* Create four transit VIFs on each Direct Connect connection and associate them with the Direct Connect gateway. A transit VIF allows you to connect to a Direct Connect gateway using a private ASN.

* Create an association between the Direct Connect gateway and the transit gateways in each Region. This will enable the on-premises location to access the VPCs that are attached to the transit gateways.

To use AWS PrivateLink, you need to create interface type VPC endpoints for the services that you want to access privately from your VPC1. These endpoints appear as elastic network interfaces (ENIs) with private IPs in your subnets2. To enable DNS resolution for these endpoints, you need to set the enableDnsSupport attribute to True for your VPC, and enable DNS support for each endpoint3. You also need to ensure that the VPC endpoint policy allows communication between your VPC and the service4. You do not need to create any route table entries or Route 53 hosted zones for the endpoints, as they are not required for PrivateLink5.

AWS PrivateLink FAQs -- Amazon Web Services 2: AWS PrivateLink and service endpoint - Amazon EC2 Overview and Networking Introduction for Telecom Companies 3: VPC Endpoints: Secure and Direct Access to AWS Services 4: AWS PrivateLink and service endpoint - Amazon EC2 Overview and Networking Introduction for Telecom Companies 5: AWS Private Link vs VPC Endpoint - Stack Overflow

The most operationally efficient way to restrict inbound traffic to the ALB to come from CloudFront is to use the AWS managed prefix list for CloudFront. A prefix list is a collection of CIDR blocks that can be used to configure security groups and network ACLs. AWS provides a managed prefix list for CloudFront that is automatically updated when CloudFront IP ranges change. By adding an inbound rule to the ALB's security group to allow the AWS managed prefix list for CloudFront, the network engineer can ensure that only CloudFront can access the ALB at the network layer. This solution does not require any additional configuration or maintenance. Option B is less efficient because network ACLs are stateless and require rules for both inbound and outbound traffic. Option C is not a network layer solution, but an application layer solution that requires the ALB to inspect the HTTP headers and reject requests that do not have the custom header. Option D is also not a network layer solution, but a web layer solution that requires AWS WAF to filter the traffic based on the CloudFront IP set. This solution also requires an AWS Lambda function to update the CloudFront IP set, which adds complexity and cost

The correct solution is to use an S3 interface endpoint and an on-premises DNS resolver. An S3 interface endpoint allows you to access Amazon S3 using private IP addresses within your VPC. An on-premises DNS resolver can be configured to forward the DNS queries for the S3 domain names to the S3 interface endpoint, so that the on-premises workloads can access Amazon S3 privately over the VPN connection. This solution is operationally efficient, as it does not require any additional infrastructure or changes to the existing workloads. The VPC workloads can continue to use the S3 gateway endpoint, which provides lower latency and higher throughput than the S3 interface endpoint.