ANS-C01 Practice Test 3 — 25 Questions

Question 1

A company uses AWS Direct Connect to connect its on-premises data center to a VPC. The network team needs to monitor the Direct Connect connection for performance issues and receive alerts when latency exceeds a certain threshold. Which TWO actions should the team take to meet these requirements? (Choose TWO.)

Accepted Answer

Create a CloudWatch alarm on the Direct Connect latency metric to send notifications when latency exceeds the threshold.. Option A is correct because AWS Direct Connect provides a built-in 'Latency' metric in CloudWatch that measures the round-trip time between the Direct Connect location and the AWS region. By creating a CloudWatch alarm on this metric, the team can trigger an SNS notification when latency exceeds a defined threshold, enabling proactive monitoring of performance issues.

Answer

Subscribe to AWS Health Dashboard events for Direct Connect.

Answer

Enable VPC Flow Logs to capture traffic patterns and latency.

Answer

Configure a VPN CloudWatch metric to monitor the Direct Connect connection.

Question 2

A company wants to enforce that all outbound traffic from its VPC flows through a centralized inspection VPC for security monitoring. The VPCs are connected via Transit Gateway. Which set of actions should a network engineer take to ensure that traffic from application VPCs is routed to the inspection VPC before reaching the internet?

Accepted Answer

Create a TGW route table with a blackhole route for 0.0.0.0/0 and associate it with application VPC attachments; attach the inspection VPC to a different TGW route table that has a route to the internet via an egress VPC.. Option D is correct because it uses separate Transit Gateway route tables to enforce traffic isolation: the application VPC attachments use a route table with a blackhole for 0.0.0.0/0, preventing direct internet access, while the inspection VPC uses a different route table with a route to an egress VPC that has an internet gateway. This ensures all outbound traffic from application VPCs must first traverse the inspection VPC for security monitoring before reaching the internet.

Answer

Create VPC peering connections between each application VPC and the inspection VPC, and add routes pointing to the peering connection.

Answer

Attach an internet gateway to each application VPC and add a default route pointing to the inspection VPC's NAT gateway.

Answer

Attach an internet gateway to each application VPC and add default route pointing to it.

Question 3

A security engineer runs tcpdump on an EC2 instance (10.0.1.5) and sees the output above. The instance is in a private subnet with a security group that allows inbound HTTPS from 0.0.0.0/0. The instance is behind a Network Load Balancer (NLB) that has a public IP. The engineer is unable to establish an HTTPS connection from the internet. What is the most likely cause?

Accepted Answer

The NLB's target group health checks are failing, causing the NLB to consider the instance unhealthy.. The tcpdump output shows the NLB's health check traffic (SYN packets from the NLB's private IPs) reaching the instance, but the engineer cannot establish an HTTPS connection from the internet. If the target group health checks are failing, the NLB marks the instance as unhealthy and stops forwarding traffic to it, which would prevent any internet HTTPS connections from reaching the instance. This is the most likely cause because the security group allows inbound HTTPS from 0.0.0.0/0, and the NLB does not preserve source IP by default, so the security group is not blocking traffic from the internet.

Answer

The NLB is not preserving the source IP, so the security group is blocking the traffic.

Answer

The instance's operating system firewall is blocking the connection.

Answer

The security group is blocking inbound traffic from the NLB.

Question 4

A security engineer is designing a security group configuration for a web application that consists of an Application Load Balancer (ALB), Amazon EC2 instances in an Auto Scaling group, and an Amazon RDS database. Which TWO actions should the engineer take to follow security best practices? (Choose TWO.)

Accepted Answer

Configure the EC2 instance security group to allow inbound traffic on port 443 from the ALB security group.. Option B is correct because referencing the ALB security group as the source in the EC2 security group rule ensures that only traffic originating from the ALB (and not any other source) is allowed on port 443. This follows the security best practice of using security group references instead of IP ranges, providing a tighter, more dynamic access control that automatically scales with the ALB's elastic network interfaces.

Answer

Configure the RDS security group to allow inbound traffic on port 3306 from 0.0.0.0/0.

Answer

Configure the ALB security group to allow inbound traffic on port 443 from the security group of the EC2 instances.

Answer

Configure the ALB security group to allow inbound traffic on port 80 from the security group of the EC2 instances.

Question 5

A company is using an AWS Transit Gateway to connect multiple VPCs and on-premises networks via Direct Connect. The network team notices that traffic from an on-premises network (CIDR 172.16.0.0/12) to a VPC (CIDR 10.0.0.0/16) is being dropped. The transit gateway route table shows a static route for 10.0.0.0/16 pointing to the VPC attachment. The Direct Connect virtual interface (VIF) is associated with the transit gateway and the on-premises router is advertising 172.16.0.0/12 via BGP. What is the most likely cause of the traffic being dropped?

Accepted Answer

The transit gateway route table does not have a route for the on-premises CIDR (172.16.0.0/12) pointing to the Direct Connect attachment.. The transit gateway route table must contain a route for the on-premises CIDR (172.16.0.0/12) pointing to the Direct Connect attachment for return traffic to be forwarded correctly. Without this route, the transit gateway has no path for traffic destined to the on-premises network, causing it to be dropped. The static route for 10.0.0.0/16 only handles traffic toward the VPC, not the return direction.

Answer

The VPC has a route that points to the transit gateway for the on-premises CIDR, causing asymmetric routing.

Answer

The Direct Connect VIF is not configured with BFD.

Answer

The VPC route table does not have a route for the on-premises CIDR pointing to the transit gateway.

Question 6

A security engineer is designing a network security architecture for a multi-account AWS environment using AWS Organizations. The company requires that all VPC flow logs be delivered to a central S3 bucket in the security account. The security engineer has created a bucket policy that grants the necessary permissions. However, flow logs from member accounts are failing to be delivered. What is the most likely cause?

Accepted Answer

The bucket policy does not include a condition that restricts access to the flow log delivery service using aws:SourceArn or aws:SourceAccount.. Option B is correct because the VPC Flow Logs delivery service uses a service-linked role to write to the destination S3 bucket. Without a condition in the bucket policy that restricts access using `aws:SourceArn` or `aws:SourceAccount`, the policy is vulnerable to the confused deputy problem, where a different AWS service or account could potentially write to the bucket. The missing condition causes the delivery to fail because the service cannot verify that the request originated from the expected source.

Answer

The member accounts have not created an IAM role with permissions to write to the central bucket.

Answer

The bucket policy does not grant write access to the member accounts' root user.

Answer

The central S3 bucket has not been configured with ACLs enabled.

Question 7

A company has a VPC with an internet-facing Application Load Balancer (ALB) that routes traffic to EC2 instances in private subnets. The security team wants to block traffic from specific geographic regions. Which AWS service should they use?

Accepted Answer

AWS WAF. Option A is correct because AWS WAF can be associated with an ALB to filter traffic based on geographic location. Option B is wrong because AWS Shield Advanced provides DDoS protection, not geographic filtering. Option C is wrong because Network ACLs do not support geographic blocking. Option D is wrong because Security Groups do not support geographic blocking.

Answer

AWS Shield Advanced

Answer

Network ACLs

Answer

Security Groups

Question 8

Match each AWS networking feature to its purpose for high availability or fault tolerance.

Accepted Answer

Elastic Load Balancer: Distributes incoming traffic across multiple targets to increase fault tolerance.. Correct matches: Elastic Load Balancer distributes traffic, Route 53 provides DNS health checks, and Global Accelerator uses anycast routing. Common confusions: ELB does not handle DNS; Route 53 does not direct traffic over the global network; Global Accelerator does not log traffic.

Answer

Elastic Load Balancer: Routes traffic based on DNS health checks.

Answer

Amazon Route 53: Improves application availability by directing traffic over the AWS global network.

Answer

AWS Global Accelerator: Captures network traffic logs for analysis.

Question 9

Match each AWS Direct Connect term to its definition.

Accepted Answer

Virtual Interface (VIF): A logical connection over a Direct Connect line that connects to a VPC or other AWS services.. Correct matches: VIF is a logical connection; Direct Connect Gateway interconnects VPCs and on-premises. Common confusions: LAG is a bundle of physical connections, not a VPN endpoint; VGW is a VPN endpoint, not a bundle.

Answer

Link Aggregation Group (LAG): The AWS VPN endpoint that provides connectivity to on-premises networks over IPsec.

Answer

Virtual Private Gateway (VGW): A bundle of multiple physical connections aggregated to increase bandwidth and provide redundancy.

Question 10

Match each AWS service or feature to its primary function in network architecture.

Accepted Answer

VPC: Isolated virtual network in AWS where you can launch resources. Correct matches: VPC is an isolated virtual network; Direct Connect is a dedicated physical connection; VPN is an encrypted internet-based connection; Route 53 is a DNS service. Common confusions include mixing Direct Connect with VPN and VPC with Direct Connect.

Answer

VPC: Dedicated physical connection from on-premises to AWS

Answer

Direct Connect: Encrypted connection over the internet to AWS

Question 11

A company has a Direct Connect connection with a private virtual interface (VIF) to a VPC. The company wants to use the same Direct Connect connection to access multiple VPCs in the same AWS Region. Which solution should the company implement?

Accepted Answer

Create a transit virtual interface on the Direct Connect connection and associate it with a Direct Connect gateway.. Option B is correct because a transit virtual interface (VIF) on a Direct Connect connection can be associated with a Direct Connect gateway, which enables connectivity to multiple VPCs in the same AWS Region. The Direct Connect gateway acts as a hub, allowing the single physical connection to route traffic to multiple VPCs via the transit VIF, without needing separate private VIFs for each VPC.

Answer

Use a public virtual interface and route traffic through the internet.

Answer

Request a hosted virtual interface from an AWS Direct Connect partner.

Answer

Create additional private virtual interfaces for each VPC.

Question 12

A company is designing a hybrid network architecture that connects an on-premises data center to AWS using AWS Direct Connect. The company requires high availability and uses BGP for dynamic routing. The on-premises router supports BGP multipath. Which configuration ensures the highest availability for the Direct Connect connection?

Accepted Answer

Provision two Direct Connect connections to two different Direct Connect locations and configure BGP multipath.. Option A is correct because provisioning two Direct Connect connections to two different Direct Connect locations eliminates single points of failure at the physical layer and the facility level. BGP multipath allows the on-premises router to load-balance traffic across both connections, maximizing availability by ensuring that if one connection or location fails, traffic continues over the other without relying on a slower failover mechanism like VPN.

Answer

Provision a single Direct Connect connection and a Site-to-Site VPN as a backup.

Answer

Provision a single Direct Connect connection with two virtual interfaces.

Answer

Provision a single Direct Connect connection with multiple VLANs.

Question 13

A company is designing a multi-region architecture with an Application Load Balancer (ALB) in us-east-1 and a Network Load Balancer (NLB) in eu-west-1. They need to route traffic from the ALB to the NLB using a fixed IP address. Which AWS service should be used to provide a static IP for the NLB and enable cross-region load balancing?

Accepted Answer

AWS Global Accelerator. AWS Global Accelerator provides two static anycast IP addresses that serve as a fixed entry point for traffic. It can route traffic from the ALB in us-east-1 to the NLB in eu-west-1 by using an endpoint group that includes the NLB's IP address, enabling cross-region load balancing with a static IP. This allows the ALB to forward traffic to the Global Accelerator's static IP, which then optimally routes to the NLB in the other region.

Answer

AWS WAF

Answer

Amazon CloudFront

Answer

AWS Transit Gateway

Question 14

A company has a Direct Connect connection with a private VIF to a VPC. They want to add a second Direct Connect connection for redundancy. Both connections will terminate at the same Direct Connect gateway. Which TWO steps are required to enable BGP multipath (ECMP) across the two connections?

Accepted Answer

Ensure the same customer-side ASN is used on both virtual interfaces.. To enable BGP multipath (ECMP) across two Direct Connect connections terminating on the same Direct Connect gateway, you must use the same customer-side ASN on both virtual interfaces. This allows the Direct Connect gateway to treat both paths as equal-cost routes. Additionally, you must advertise the same BGP prefixes on both virtual interfaces so that the gateway sees identical routes from both paths and can load-balance traffic across them.

Answer

Use a different autonomous system number (ASN) on each virtual interface.

Answer

Advertise different BGP prefixes on each virtual interface.

Answer

Attach each virtual interface to a different VPC.

Question 15

A company is designing a network for a multi-account AWS environment using AWS Organizations. They need to establish a central inspection VPC for traffic inspection using a Gateway Load Balancer (GWLB). Traffic from all other VPCs should be routed through the inspection VPC before reaching the internet or on-premises. Which architecture should be used?

Accepted Answer

Use AWS Transit Gateway with a centralized inspection VPC that hosts a GWLB. Configure route tables on the Transit Gateway to send traffic to the GWLB endpoint.. Option C is correct because AWS Transit Gateway enables centralized routing between multiple VPCs, and when combined with a Gateway Load Balancer (GWLB) in an inspection VPC, it allows traffic from all other VPCs to be forwarded to the GWLB for inspection before reaching the internet or on-premises. Transit Gateway route tables can be configured with static routes pointing to the GWLB endpoint (using Gateway Load Balancer Endpoint service), ensuring all inter-VPC and egress traffic is steered through the inspection VPC. This architecture scales efficiently across many VPCs in an AWS Organizations multi-account setup without requiring complex peering or direct connections.

Answer

Use VPC Peering to connect all VPCs to the inspection VPC and configure routes to the GWLB.

Answer

Use AWS Direct Connect Gateway to connect all VPCs and route traffic through the inspection VPC.

Answer

Use AWS Network Firewall in each VPC and route traffic to it.

Question 16

A company is deploying a multi-tier application in a VPC. The web tier is in public subnets, and the application tier is in private subnets. The application tier needs to communicate with an on-premises database via an AWS Direct Connect connection. The company wants to minimize latency and maximize throughput. Which design should they use?

Accepted Answer

Place the application tier instances in a private subnet in the same VPC as the web tier. Attach a virtual private gateway to the VPC and connect it to the on-premises network via a Direct Connect private virtual interface.. Option A is correct because a Direct Connect private virtual interface (VIF) connected to a virtual private gateway (VGW) provides a dedicated, low-latency, high-throughput connection from the VPC to on-premises. The application tier in the private subnet can route traffic directly to the on-premises database via the VGW without traversing the internet or a NAT device, minimizing latency and maximizing throughput.

Answer

Place the application tier in a private subnet and use a NAT Gateway to route traffic to the on-premises network.

Answer

Place the application tier in a separate VPC and peer it to the web tier VPC. Use a Direct Connect connection attached to the web tier VPC.

Answer

Place the application tier in a separate VPC and use a VPN connection over the internet to connect to on-premises.

Question 17

A company has a VPC with public and private subnets in three Availability Zones. They have an Application Load Balancer (ALB) in the public subnets and a fleet of EC2 instances in the private subnets. The ALB needs to send traffic to the instances on port 443. What is the most secure way to configure the security groups?

Accepted Answer

ALB SG: inbound from 0.0.0.0/0 on port 443. Instance SG: inbound from ALB SG on port 443.. Option C is correct because it follows the principle of least privilege by restricting the ALB security group to only allow inbound traffic on port 443 from the internet (0.0.0.0/0) and the instance security group to only allow inbound traffic on port 443 from the ALB security group. This ensures that only the ALB can communicate with the instances on the required port, preventing direct access from other sources and reducing the attack surface.

Answer

ALB SG: inbound from 0.0.0.0/0 on all ports. Instance SG: inbound from ALB SG on all ports.

Answer

ALB SG: inbound from 0.0.0.0/0 on port 443. Instance SG: inbound from 0.0.0.0/0 on port 443.

Answer

ALB SG: inbound from 0.0.0.0/0 on port 443. Instance SG: inbound from ALB SG on all ports.

Question 18

A company wants to monitor network traffic between two VPCs that are peered. Which AWS feature can capture IP traffic information for analysis?

Accepted Answer

VPC Flow Logs. VPC Flow Logs capture IP traffic information for network interfaces in a VPC, including traffic between peered VPCs. They log metadata such as source/destination IPs, ports, protocols, and packet accept/reject decisions, which can be published to CloudWatch Logs or Amazon S3 for analysis. This makes them the correct choice for monitoring network traffic between two peered VPCs.

Answer

AWS X-Ray

Answer

AWS Config

Answer

AWS CloudTrail

Question 19

A company wants to monitor network traffic in their VPC for troubleshooting and security analysis. They need to capture IP traffic information, including source/destination IPs, ports, and protocol, but not the packet payload. Which AWS service should be used?

Accepted Answer

VPC Flow Logs.. VPC Flow Logs capture metadata about IP traffic in a VPC, including source/destination IPs, ports, protocol, and packet counts, but never the payload. This meets the requirement for troubleshooting and security analysis without the overhead or privacy concerns of full packet capture.

Answer

Amazon CloudWatch Logs.

Answer

AWS Network Firewall.

Answer

AWS Traffic Mirroring.

Question 20

A company is using AWS Transit Gateway to connect multiple VPCs and an on-premises network via AWS Direct Connect. They need to ensure that traffic between VPCs is inspected by a centralized security appliance. How should they design the routing?

Accepted Answer

Create a Transit Gateway with separate route tables. Attach each VPC and the Direct Connect virtual interface to the Transit Gateway. In the route tables, propagate routes and add static routes to send inter-VPC traffic to the security appliance VPC.. Option D is correct because AWS Transit Gateway supports separate route tables, allowing you to isolate traffic domains. By attaching each VPC and the Direct Connect virtual interface to the Transit Gateway, you can create a centralized inspection VPC. Static routes in the Transit Gateway route tables direct inter-VPC traffic to the security appliance VPC, ensuring all traffic between VPCs is inspected before reaching its destination.

Answer

Use Network ACLs on the subnets to restrict traffic and allow inspection.

Answer

Create VPC peering connections between all VPCs and route traffic through a security appliance in a central VPC.

Answer

Use security groups on the security appliance to inspect traffic.