ANS-C01 Practice Exam 4 — 20 Questions

Question 1

A company is using AWS Transit Gateway to interconnect multiple VPCs and on-premises networks. The network team wants to log and monitor all traffic flows across the Transit Gateway for security analysis. Which TWO actions should the team take? (Choose TWO.)

Accepted Answer

Send the flow logs to Amazon CloudWatch Logs for monitoring and alerting.. Option B is correct because VPC Flow Logs can be published to Amazon CloudWatch Logs, enabling real-time monitoring, alerting, and integration with AWS Lambda or third-party tools for security analysis. This allows the network team to capture IP traffic information for all flows across Transit Gateway attachments when flow logs are enabled on those attachments. Option C is correct because VPC Flow Logs must be enabled at the Transit Gateway attachment level (not on the Transit Gateway itself) to capture traffic traversing the Transit Gateway, as the Transit Gateway is a network transit hub and does not generate its own flow logs.

Answer

Use AWS Config rules to evaluate the Transit Gateway route tables.

Answer

Enable VPC Flow Logs on the Transit Gateway itself.

Answer

Configure VPC Traffic Mirroring on the Transit Gateway.

Question 2

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 3

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 4

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 5

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 6

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 7

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 8

Arrange the steps to configure an AWS Client VPN endpoint for remote access:

Question 9

Order the steps to set up a redundant Direct Connect connection with two virtual interfaces in different AWS regions:

Question 10

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

Question 11

Match each AWS networking feature to its use case for hybrid connectivity.

Question 12

Match each AWS Direct Connect term to its definition.

Question 13

Match each AWS networking monitoring or troubleshooting tool to its primary purpose.

Question 14

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

Question 15

Match each AWS networking service to the OSI layer it primarily operates at.

Question 16

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 17

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 18

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 19

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 20

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.