Amazon Web Services CLF-C02 Exam With Confidence Using Practice Dumps

 Security groups are the service or feature that meets the requirement of establishing a security layer in a VPC that will act as a firewall to control subnet traffic. Security groups are stateful firewalls that control the inbound and outbound traffic at the instance level. You can assign one or more security groups to each instance in a VPC, and specify the rules that allow or deny traffic based on the protocol, port, and source or destination. Security groups are associated with network interfaces, and therefore apply to all the instances in the subnets that use those network interfaces. Routing tables are used to direct traffic between subnets and gateways, not to filter traffic. Network ACLs are stateless firewalls that control the inbound and outbound traffic at the subnet level, but they are less granular and more cumbersome to manage than security groups. Amazon GuardDuty is a threat detection service that monitors your AWS account and workloads for malicious or unauthorized activity, not a firewall service.

Deploying the application by using multiple Availability Zones is the best way to increase resilience for the application. According to the Amazon RDS User Guide, "Amazon RDS provides high availability and failover support for DB instances using Multi-AZ deployments. In a Multi-AZ deployment, Amazon RDS automatically provisions and maintains a synchronous standby replica in a different Availability Zone. The primary DB instance is synchronously replicated across Availability Zones to a standby replica to provide data redundancy, eliminate I/O freezes, and minimize latency spikes during system backups."4 Deploying a copy of the application in another AWS account, using multiple VPCs, or using multiple subnets do not provide the same level of resilience as using multiple Availability Zones.

The correct answer is B because placing the EC2 instances in two separate Availability Zones within the same AWS Region is the best way to meet the requirement. Availability Zones are isolated locations within an AWS Region that have independent power, cooling, and networking. Users can launch their resources, such as Amazon EC2 instances, in multiple Availability Zones to increase the fault tolerance and resilience of their applications. Availability Zones within the same AWS Region are connected with low-latency, high-throughput, and highly redundant networking. The other options are incorrect because they are not the best ways to meet the requirement. Placing the EC2 instances in two separate AWS Regions connected with a VPC peering connection is not the best way to meet the requirement because AWS Regions are geographically dispersed and may have higher communication latency between them than Availability Zones within the same AWS Region. VPC peering connection is a networking connection between two VPCs that enables users to route traffic between them using private IP addresses. Placing one EC2 instance on premises and the other in an AWS Region, and then connecting them by using an AWS VPN connection is not the best way to meet the requirement because on-premises and AWS Region are geographically dispersed and may have higher communication latency between them than Availability Zones within the same AWS Region. AWS VPN connection is a secure and encrypted connection between a user’s network and their VPC. Placing both EC2 instances in a placement group for dedicated bandwidth is not the best way to meet the requirement because a placement group is a logical grouping of instances within a single Availability Zone that enables users to launch instances with specific performance characteristics. A placement group does not ensure that the instances are in separate data centers, and it does not provide low-latency communication between instances in different AvailabilityZones. Reference: [Regions, Availability Zones, and Local Zones], [VPC Peering], [AWS VPN], [Placement Groups]