AWS Certified Advanced Networking - Specialty ANS-C01 Practice Test 84
Question 830
For this AWS/hybrid networking scenario—One Site-to-Site VPN tunnel is healthy but a peer refuses incoming routes because of a prefix filter—which action should the engineer take?
- Correct GRE tunnel parameters, BGP session details, and Connect peer routing
- Correct the customer route filter to accept and advertise the intended network prefixes
- Validate dynamic routing preference and backup advertisements before fault injection
- Configure both AWS-provided tunnels with monitored backup operation
Explanation
Correct Answer
B:Correct the customer route filter to accept and advertise the intended network prefixes. The stated configuration and business requirement call for this change because tunnel establishment and routing prefix acceptance are distinct steps in working connectivity. Leaving the existing gap unresolved could mean that an IPsec-up tunnel does not guarantee the required subnet route is installed. Confirm the improvement by showing that customer and AWS route tables contain the authorized destination prefixes.
Incorrect Answers
A:Correct GRE tunnel parameters, BGP session details, and Connect peer routing would address a different scenario, such as when a company uses a Transit Gateway Connect attachment to carry SD-WAN routes but the overlay peer is not Established. The present issue requires correct the customer route filter to accept and advertise the intended network prefixes because the network path and control point are different; the alternative does not directly meet this requirement.
C:Validate dynamic routing preference and backup advertisements before fault injection would address a different scenario, such as when the Direct Connect physical port is down but the application must automatically use an existing backup VPN. The present issue requires correct the customer route filter to accept and advertise the intended network prefixes because the network path and control point are different; the alternative does not directly meet this requirement.
D:Configure both AWS-provided tunnels with monitored backup operation would address a different scenario, such as when an enterprise provisions a VPN but only one of its provided tunnel endpoint configurations is deployed. The present issue requires correct the customer route filter to accept and advertise the intended network prefixes because the network path and control point are different; the alternative does not directly meet this requirement.
Question 831
AWS architects plan to Replace hardcoded environment identifiers with parameters, discovery and account-scoped outputs for this requirement: A multi-account transit network uses fixed VPC IDs in scripts and deployment to new accounts fails. Which principle is MOST relevant?
- Compliance evaluation should drive timely notification or controlled auto-remediation
- Tags support inventory, ownership and governance but require policy enforcement for consistency
- IaC templates should resolve environment-specific identifiers rather than assuming global IDs
- Network automation must reconcile reference dependencies before destructive actions
Explanation
Correct Answer
C:IaC templates should resolve environment-specific identifiers rather than assuming global IDs. This mechanism directly explains why the proposed change, replace hardcoded environment identifiers with parameters, discovery and account-scoped outputs, fits this particular packet path or control requirement. Without it, copying a raw VPC ID across accounts creates nonexistent or wrong-target references. A suitable verification is that the same template deploys with unique IDs and correct attachment references per account.
Incorrect Answers
A:Compliance evaluation should drive timely notification or controlled auto-remediation explains a different case, for example when an AWS Config rule finds unauthorized changes in VPC route tables but nobody learns about them until audit time. In the current topology, the deciding factor is that iaC templates should resolve environment-specific identifiers rather than assuming global IDs; this choice therefore does not explain the specified remedy.
B:Tags support inventory, ownership and governance but require policy enforcement for consistency explains a different case, for example when a network organization wants consistent subnet and Transit Gateway attachment tagging across all business accounts. In the current topology, the deciding factor is that iaC templates should resolve environment-specific identifiers rather than assuming global IDs; this choice therefore does not explain the specified remedy.
D:Network automation must reconcile reference dependencies before destructive actions explains a different case, for example when a team deletes old security groups using a cron job but removes groups still referenced by ENIs. In the current topology, the deciding factor is that iaC templates should resolve environment-specific identifiers rather than assuming global IDs; this choice therefore does not explain the specified remedy.
Question 832
A team faces this situation: A site VPN fails at regular intervals due to expired or incompatible Internet Key Exchange settings. It proposes: Review supported IKE/IPsec parameters, rekey policy and peer configuration. What underlying networking principle BEST explains this decision?
- Endpoint-specific DNS names and ENI addresses can change through resource replacement
- Longest-prefix matching can override preferred BGP paths for different network ranges
- Primary and backup link selection can change when policy and prefix specificity differ
- Cryptographic security association lifetimes and compatible algorithms affect tunnel stability
Explanation
Correct Answer
D:Cryptographic security association lifetimes and compatible algorithms affect tunnel stability. This mechanism directly explains why the proposed change, review supported IKE/IPsec parameters, rekey policy and peer configuration, fits this particular packet path or control requirement. Without it, adding another application subnet will not repair repeated tunnel negotiation failures. A suitable verification is that tunnel renegotiation succeeds across the expected maintenance and rekey intervals.
Incorrect Answers
A:Endpoint-specific DNS names and ENI addresses can change through resource replacement explains a different case, for example when a VPC interface endpoint is deleted and recreated but scripts still target the former endpoint DNS name. In the current topology, the deciding factor is that cryptographic security association lifetimes and compatible algorithms affect tunnel stability; this choice therefore does not explain the specified remedy.
B:Longest-prefix matching can override preferred BGP paths for different network ranges explains a different case, for example when a VPN route from a customer site suddenly loses preference to a newly advertised overlapping longer prefix. In the current topology, the deciding factor is that cryptographic security association lifetimes and compatible algorithms affect tunnel stability; this choice therefore does not explain the specified remedy.
C:Primary and backup link selection can change when policy and prefix specificity differ explains a different case, for example when a standby Direct Connect link becomes preferred unexpectedly after a policy migration. In the current topology, the deciding factor is that cryptographic security association lifetimes and compatible algorithms affect tunnel stability; this choice therefore does not explain the specified remedy.
Question 833
An engineer selects the change "Use physically diverse Direct Connect connections and redundancy designs meeting the resiliency target" because Two on-premises data centers require dedicated diverse private circuits to critical AWS Regions. Which technical explanation BEST supports it?
- Direct Connect high availability depends on independent locations and devices, not merely two VLANs
- Direct Connect gateway enables supported private routing connectivity to eligible gateways
- A public VIF exchanges suitable public routes to AWS public endpoints rather than arbitrary private VPC prefixes
- Prefix overlap and route preference can silently divert traffic to unintended networks
Explanation
Correct Answer
A:Direct Connect high availability depends on independent locations and devices, not merely two VLANs. This mechanism directly explains why the proposed change, use physically diverse Direct Connect connections and redundancy designs meeting the resiliency target, fits this particular packet path or control requirement. Without it, creating two VIFs on one router does not eliminate shared physical failure. A suitable verification is that a documented diverse-link failure test keeps the hybrid application reachable.
Incorrect Answers
B:Direct Connect gateway enables supported private routing connectivity to eligible gateways explains a different case, for example when a company needs private access to many VPCs through one dedicated connection without individual VIF per VPC. In the current topology, the deciding factor is that direct Connect high availability depends on independent locations and devices, not merely two VLANs; this choice therefore does not explain the specified remedy.
C:A public VIF exchanges suitable public routes to AWS public endpoints rather than arbitrary private VPC prefixes explains a different case, for example when a corporate office needs AWS public service endpoints over a dedicated public routing path without private VPC address exchange. In the current topology, the deciding factor is that direct Connect high availability depends on independent locations and devices, not merely two VLANs; this choice therefore does not explain the specified remedy.
D:Prefix overlap and route preference can silently divert traffic to unintended networks explains a different case, for example when an on-premises route is summarized too broadly and overlaps multiple cloud address ranges. In the current topology, the deciding factor is that direct Connect high availability depends on independent locations and devices, not merely two VLANs; this choice therefore does not explain the specified remedy.
Question 834
What failure mode is MOST relevant if a team ignores this issue: An S3 static asset origin behind CloudFront must deny direct anonymous bucket reads?
- Network Load Balancer alone does not provide equivalent HTTP cache and WAF request inspection
- Making the S3 bucket public undermines the intended CloudFront-only distribution boundary
- Caching authenticated content under a shared key can disclose another customer's document
- Assuming every accelerator endpoint preserves the original source address can break allowlists
Explanation
Correct Answer
B:Making the S3 bucket public undermines the intended CloudFront-only distribution boundary. The missing control matters because origin access control lets CloudFront fetch private S3 objects through supported signed requests. The appropriate corrective action is to use CloudFront origin access control with a scoped S3 bucket policy. To check the outcome, verify that the CloudFront URL serves expected assets and direct anonymous S3 GET is denied.
Incorrect Answers
A:Network Load Balancer alone does not provide equivalent HTTP cache and WAF request inspection can be a real consequence when a web application needs HTTP edge caching and WAF protection but was placed behind a TCP-only NLB. Here the relevant failure is that making the S3 bucket public undermines the intended CloudFront-only distribution boundary. The alternative names a different failure mode and does not best account for the stated condition.
C:Caching authenticated content under a shared key can disclose another customer's document can be a real consequence when an application serves large personalized private documents and must prevent one user's cached response reaching another. Here the relevant failure is that making the S3 bucket public undermines the intended CloudFront-only distribution boundary. The alternative names a different failure mode and does not best account for the stated condition.
D:Assuming every accelerator endpoint preserves the original source address can break allowlists can be a real consequence when an enterprise must preserve source-client IP for a global TCP service using an accelerator and regional targets. Here the relevant failure is that making the S3 bucket public undermines the intended CloudFront-only distribution boundary. The alternative names a different failure mode and does not best account for the stated condition.
Question 835
AWS architects plan to Reconcile endpoint-service permissions, acceptance state, and private DNS configuration for this requirement: A service needs a private cross-account endpoint but a deployment removed its consumer endpoint acceptance. Which principle is MOST relevant?
- Private routed connectivity requires symmetric return routing and compatible network controls
- Asymmetric hybrid routing can break stateful firewall connection tracking
- PrivateLink connectivity depends on service authorization as well as endpoint ENI reachability
- Cryptographic security association lifetimes and compatible algorithms affect tunnel stability
Explanation
Correct Answer
C:PrivateLink connectivity depends on service authorization as well as endpoint ENI reachability. This mechanism directly explains why the proposed change, reconcile endpoint-service permissions, acceptance state, and private DNS configuration, fits this particular packet path or control requirement. Without it, recreating the provider ALB does not approve a rejected consumer endpoint. A suitable verification is that the intended consumer endpoint becomes Available and service calls succeed.
Incorrect Answers
A:Private routed connectivity requires symmetric return routing and compatible network controls explains a different case, for example when a VPC peering change broke one direction of a database connection but the forward route is present. In the current topology, the deciding factor is that privateLink connectivity depends on service authorization as well as endpoint ENI reachability; this choice therefore does not explain the specified remedy.
B:Asymmetric hybrid routing can break stateful firewall connection tracking explains a different case, for example when a local firewall routes database traffic via Direct Connect but the AWS VPC return route points to VPN. In the current topology, the deciding factor is that privateLink connectivity depends on service authorization as well as endpoint ENI reachability; this choice therefore does not explain the specified remedy.
D:Cryptographic security association lifetimes and compatible algorithms affect tunnel stability explains a different case, for example when a site VPN fails at regular intervals due to expired or incompatible Internet Key Exchange settings. In the current topology, the deciding factor is that privateLink connectivity depends on service authorization as well as endpoint ENI reachability; this choice therefore does not explain the specified remedy.
Question 836
An AWS network architect encounters this situation: A compliance team must audit DNS usage for malicious domains from workloads that use VPC resolver. Which change BEST meets the documented requirement?
- Run Reachability Analyzer negative-path tests after relevant network changes
- Enable suitable AWS Config recording and network-related compliance evaluations
- Centralize eligible service logs to approved S3 or log ingestion with scoped retention and encryption
- Collect Route 53 Resolver query logs with account-aware storage and access policy
Explanation
Correct Answer
D:Collect Route 53 Resolver query logs with account-aware storage and access policy. The stated configuration and business requirement call for this change because resolver query logging records names and client context for associated VPC resolution. Leaving the existing gap unresolved could mean that cloudTrail Route 53 API logs do not enumerate every DNS lookup by an instance. Confirm the improvement by showing that test resolver queries are retained with origin context and required permissions.
Incorrect Answers
A:Run Reachability Analyzer negative-path tests after relevant network changes would address a different scenario, such as when a security reviewer needs a repeatable audit that production VPC paths cannot reach a prohibited subnet. The present issue requires collect Route 53 Resolver query logs with account-aware storage and access policy because the network path and control point are different; the alternative does not directly meet this requirement.
B:Enable suitable AWS Config recording and network-related compliance evaluations would address a different scenario, such as when an auditor asks for evidence that prohibited network routes are detected if changed outside IaC. The present issue requires collect Route 53 Resolver query logs with account-aware storage and access policy because the network path and control point are different; the alternative does not directly meet this requirement.
C:Centralize eligible service logs to approved S3 or log ingestion with scoped retention and encryption would address a different scenario, such as when a company needs to preserve compliance evidence from ALB, CloudFront, and Network Firewall in one protected location. The present issue requires collect Route 53 Resolver query logs with account-aware storage and access policy because the network path and control point are different; the alternative does not directly meet this requirement.
Question 837
For this networking situation, An international API needs path-based origin routing while protecting the origin from direct public use, the team applies "Configure CloudFront behavior routing and supported origin access restrictions". Which validation is strongest?
- Expected paths reach their intended origin and unauthorized direct-origin requests fail
- Repeated eligible responses are served at edges and blocked HTTP requests do not reach origin
- Viewer traces resolve to edge delivery and the origin receives only needed fetches
- Clients retain the same advertised addresses when the unhealthy Region loses traffic
Explanation
Correct Answer
A:Expected paths reach their intended origin and unauthorized direct-origin requests fail. This directly tests whether the selected change, configure CloudFront behavior routing and supported origin access restrictions, achieved the intended network outcome. The key mechanism is that cloudFront behaviors can select origins by path and gate the supported origin access pattern. The incident or compliance risk being reduced was that an unrestricted origin endpoint bypasses edge policies and may be directly abused.
Incorrect Answers
B:Repeated eligible responses are served at edges and blocked HTTP requests do not reach origin might confirm another remediation, for instance when a web application needs HTTP edge caching and WAF protection but was placed behind a TCP-only NLB. This question instead requires demonstrating that expected paths reach their intended origin and unauthorized direct-origin requests fail. The alternative would not validate the selected network fix.
C:Viewer traces resolve to edge delivery and the origin receives only needed fetches might confirm another remediation, for instance when a website requires viewers in distant locations to reach the nearest available HTTP edge with HTTPS termination. This question instead requires demonstrating that expected paths reach their intended origin and unauthorized direct-origin requests fail. The alternative would not validate the selected network fix.
D:Clients retain the same advertised addresses when the unhealthy Region loses traffic might confirm another remediation, for instance when a trading client needs static anycast IP addresses and TCP endpoint failover across Regions. This question instead requires demonstrating that expected paths reach their intended origin and unauthorized direct-origin requests fail. The alternative would not validate the selected network fix.
Question 838
Following remediation of "A global video publisher has high origin load because viewers repeatedly request the same public media files", what evidence MOST directly establishes that it works?
- Clients retain the same advertised addresses when the unhealthy Region loses traffic
- Cache hit ratio rises and origin request volume falls under equivalent viewer load
- Existing endpoint configuration remains constant while new UDP traffic shifts to a healthy Region
- Cross-user tests cannot retrieve each other's objects while authorized retrieval succeeds
Explanation
Correct Answer
B:Cache hit ratio rises and origin request volume falls under equivalent viewer load. This directly tests whether the selected change, use CloudFront cache behaviors with suitable TTL and origin request policies, achieved the intended network outcome. The key mechanism is that cloudFront edge caching reduces repetitive origin fetches for cacheable content. The incident or compliance risk being reduced was that sending every request to one Region adds latency and unnecessary origin traffic.
Incorrect Answers
A:Clients retain the same advertised addresses when the unhealthy Region loses traffic might confirm another remediation, for instance when a trading client needs static anycast IP addresses and TCP endpoint failover across Regions. This question instead requires demonstrating that cache hit ratio rises and origin request volume falls under equivalent viewer load. The alternative would not validate the selected network fix.
C:Existing endpoint configuration remains constant while new UDP traffic shifts to a healthy Region might confirm another remediation, for instance when a multiplayer client cannot tolerate DNS change delays during regional failure and uses UDP transport. This question instead requires demonstrating that cache hit ratio rises and origin request volume falls under equivalent viewer load. The alternative would not validate the selected network fix.
D:Cross-user tests cannot retrieve each other's objects while authorized retrieval succeeds might confirm another remediation, for instance when an application serves large personalized private documents and must prevent one user's cached response reaching another. This question instead requires demonstrating that cache hit ratio rises and origin request volume falls under equivalent viewer load. The alternative would not validate the selected network fix.
Question 839
A team chooses to Compare NLB target group registration, health check listener and application port after observing: An NLB target is unhealthy while TCP traffic is delivered to a different instance by a manually configured DNS override. Which result would BEST verify the change?
- UDP test packets and replies traverse each approved filter with expected listener behavior
- Fresh tasks launch after verified address capacity is provided
- Corrected target registration becomes healthy and client sessions reach the intended service
- A deliberate deny change causes the path gate to fail before production promotion
Explanation
Correct Answer
C:Corrected target registration becomes healthy and client sessions reach the intended service. This directly tests whether the selected change, compare NLB target group registration, health check listener and application port, achieved the intended network outcome. The key mechanism is that load-balancer health and client name resolution both affect which service receives packets. The incident or compliance risk being reduced was that a green EC2 status check does not prove a target group's application probe passes.
Incorrect Answers
A:UDP test packets and replies traverse each approved filter with expected listener behavior might confirm another remediation, for instance when an EC2 instance drops UDP while TCP works and a team assumes the security group must be the only blocker. This question instead requires demonstrating that corrected target registration becomes healthy and client sessions reach the intended service. The alternative would not validate the selected network fix.
B:Fresh tasks launch after verified address capacity is provided might confirm another remediation, for instance when a subnet has enough addresses on paper but ECS tasks cannot create ENIs in one availability zone. This question instead requires demonstrating that corrected target registration becomes healthy and client sessions reach the intended service. The alternative would not validate the selected network fix.
D:A deliberate deny change causes the path gate to fail before production promotion might confirm another remediation, for instance when a production team wants a repeatable signal that approved VPC path permissions remain intact after each change. This question instead requires demonstrating that corrected target registration becomes healthy and client sessions reach the intended service. The alternative would not validate the selected network fix.
Question 840
The team addressed this problem: A distributed branch solution needs SD-WAN appliance integration with Transit Gateway using overlay tunnels. Which observation BEST demonstrates the required result?
- Measured sustained tunnel latency and loss improve under matching supported conditions
- A documented diverse-link failure test keeps the hybrid application reachable
- A controlled loss of either customer router leaves an independent hybrid route active
- Overlay BGP neighbors form and selected branch prefixes reach their AWS destinations
Explanation
Correct Answer
D:Overlay BGP neighbors form and selected branch prefixes reach their AWS destinations. This directly tests whether the selected change, consider Transit Gateway Connect with compatible GRE and BGP overlay capabilities, achieved the intended network outcome. The key mechanism is that transit Gateway Connect supports SD-WAN overlay connectivity through the supported attachment model. The incident or compliance risk being reduced was that a generic Site-to-Site VPN connection does not provide the same managed GRE Connect pattern.
Incorrect Answers
A:Measured sustained tunnel latency and loss improve under matching supported conditions might confirm another remediation, for instance when a remote office experiences internet variability to the selected AWS VPN region and wants improved entry routing. This question instead requires demonstrating that overlay BGP neighbors form and selected branch prefixes reach their AWS destinations. The alternative would not validate the selected network fix.
B:A documented diverse-link failure test keeps the hybrid application reachable might confirm another remediation, for instance when two on-premises data centers require dedicated diverse private circuits to critical AWS Regions. This question instead requires demonstrating that overlay BGP neighbors form and selected branch prefixes reach their AWS destinations. The alternative would not validate the selected network fix.
C:A controlled loss of either customer router leaves an independent hybrid route active might confirm another remediation, for instance when a data center wants high availability but two VPN tunnels terminate on the same failing customer device. This question instead requires demonstrating that overlay BGP neighbors form and selected branch prefixes reach their AWS destinations. The alternative would not validate the selected network fix.