Question 670
An AWS network engineer must address this specific condition: A routing change was deployed, and the team needs to prove a critical source should remain unable to reach a sensitive subnet. Which implementation or operational change BEST meets the requirement?
- Use appropriate ALB, proxy or application access logs to identify HTTP paths.
- Mirror the affected ENI traffic to a packet analyzer using suitable filters.
- Run Route Analyzer for the source and destination attachments with the expected route tables.
- Execute a scoped source-to-destination path analysis using the intended transport port.
Explanation
Correct Answer
D:Negative reachability intent is a valid test: an unreachable result can be correct for restricted networks. Confirm the change by checking that the forbidden path remains blocked with an identifiable intentional control.
Incorrect Answers
A:Layer-three/four flow metadata cannot reveal encrypted HTTP resource paths. That adjustment does not address the controlling condition: negative reachability intent is a valid test: an unreachable result can be correct for restricted networks. Verify the forbidden path remains blocked with an identifiable intentional control.
B:VPC Flow Logs cannot reconstruct full TCP handshake packet order from aggregated records. In this situation, negative reachability intent is a valid test: an unreachable result can be correct for restricted networks. The proposed change does not ensure the forbidden path remains blocked with an identifiable intentional control.
C:The hub's internal route selection can differ from VPC subnet routes and needs separate evaluation. The needed control instead targets reachability Analyzer can validate that a forbidden path remains blocked by configured network controls; it succeeds when the forbidden path remains blocked with an identifiable intentional control.
Question 671
In an AWS networking assessment, a telecommunications customer needs to prove that confidential BGP-routed traffic over a dedicated Direct Connect line is not exposed as plaintext to intermediate transport operators. Which technical explanation BEST accounts for the observed condition?
- Private dedicated interconnect does not replace encryption for confidential hybrid application payloads.
- TLS termination at the load balancer does not automatically encrypt the load-balancer-to-target connection.
- AWS Site-to-Site VPN provides IPsec encryption and authentication between configured gateway endpoints.
- Private key confidentiality is required regardless of the public visibility of certificate files.
Explanation
Correct Answer
A:A private physical circuit and confidentiality cryptography solve different aspects of transport trust. This explains the observed network behavior, which can be checked by verifying that a controlled packet capture verifies encrypted sensitive payloads without altering permitted private routes.
Incorrect Answers
B:End-to-end confidentiality requires securing both client-to-ALB and ALB-to-target legs when policy demands. For the stated conditions, a private physical circuit and confidentiality cryptography solve different aspects of transport trust. The more specific mechanism is private dedicated interconnect does not replace encryption for confidential hybrid application payloads.
C:IPsec protects network traffic on untrusted transport independently of application-layer encryption. That property alone cannot account for the reported symptom; a private physical circuit and confidentiality cryptography solve different aspects of transport trust.
D:Possession of the server private key enables impersonation even when its certificate is public. The decisive technical distinction is private dedicated interconnect does not replace encryption for confidential hybrid application payloads; a private physical circuit and confidentiality cryptography solve different aspects of transport trust.
Question 672
In an AWS networking assessment, a central Transit Gateway attachment is present, but the route back to an on-premises prefix points to a wrong VPC instead of the VPN. Which technical explanation BEST accounts for the observed condition?
- Adding hybrid CIDRs requires reviewing on-premises firewall and routing policy in both directions.
- The TGW routing table must select the VPN or Direct Connect attachment for the on-premises destination.
- Transit Gateway route propagation requires the VPN attachment to propagate its eligible dynamic routes into the used route table.
- Routing from application subnets needs destination entries targeting the correct hybrid gateway path.
Explanation
Correct Answer
B:Gateway attachments are route targets; incorrect associations can blackhole return flows despite healthy tunnels. This explains the observed network behavior, which can be checked by verifying that packet path analysis shows traffic returning through the intended hybrid gateway.
Incorrect Answers
A:A BGP route to a network does not grant permission through intermediate stateful firewalls. That property alone cannot account for the reported symptom; gateway attachments are route targets; incorrect associations can blackhole return flows despite healthy tunnels.
C:A healthy VPN tunnel does not automatically install every required prefix into every TGW routing domain. The reported evidence instead concerns the TGW routing table must select the VPN or Direct Connect attachment for the on-premises destination: gateway attachments are route targets; incorrect associations can blackhole return flows despite healthy tunnels.
D:An active VIF and BGP session do not automatically override VPC subnet forwarding decisions. For the stated conditions, gateway attachments are route targets; incorrect associations can blackhole return flows despite healthy tunnels. The more specific mechanism is the TGW routing table must select the VPN or Direct Connect attachment for the on-premises destination.
Question 673
An AWS network engineer must address this specific condition: A security administrator wants proof of which IAM principal changed a VPC route table at a specific time. Which implementation or operational change BEST meets the requirement?
- Enable supported AWS Config recording and retrieve change history for the networking resource.
- Use a suitable AWS Config managed or custom rule to detect unapproved public ingress.
- Enable relevant Config recording and reconcile detected route differences through approved IaC.
- Search organization CloudTrail management events for the route-table modification action.
Explanation
Correct Answer
D:A management-plane audit trail attributes configuration changes, unlike aggregated data-plane flow records. Confirm the change by checking that the route change is linked to the responsible principal and request parameters.
Incorrect Answers
A:Configuration history provides a time series of supported resource states beyond the current console view. It does not directly achieve the required result: the route change is linked to the responsible principal and request parameters. The constraint is that a management-plane audit trail attributes configuration changes, unlike aggregated data-plane flow records.
B:Continuous configuration assessment complements packet monitoring by measuring deployed control state. The needed control instead targets cloudTrail management events record supported AWS API operations with actor, time and request context; it succeeds when the route change is linked to the responsible principal and request parameters.
C:An IaC deployment does not continuously prevent later manual console mutations. It does not directly achieve the required result: the route change is linked to the responsible principal and request parameters. The constraint is that a management-plane audit trail attributes configuration changes, unlike aggregated data-plane flow records.
Question 674
In an AWS networking assessment, an EC2 application cannot initiate TCP 5432 to its database because the database security group does not allow that client flow; an operator proposes adding arbitrary ephemeral return-port rules instead. Which technical explanation BEST accounts for the observed condition?
- Interface endpoint ENI security groups can restrict client traffic to specific approved sources.
- Security groups are stateful: replies to an allowed connection are tracked, but a new database connection still needs the initial direction permitted.
- Network ACLs are stateless and require independent rules for inbound requests and outbound responses.
- AWS Network Firewall supports stateful rule groups for protocol-aware inspection in governed VPC paths.
Explanation
Correct Answer
B:Missing permission for the initiating connection is not repaired by adding inbound return-port rules; tracked replies to allowed flows are already permitted. This explains the behavior, which can be checked by verifying that the app establishes its authorized database connection and receives responses without unrelated ephemeral return-port rules.
Incorrect Answers
A:Endpoint private addressing does not automatically enforce least-privilege client access. The decisive technical distinction is security groups are stateful: replies to an allowed connection are tracked, but a new database connection still needs the initial direction permitted; missing permission for the initiating connection is not repaired by adding inbound return-port rules; tracked replies to allowed flows are already permitted.
C:A successful inbound rule does not automatically authorize reply packets under a stateless ACL. For the stated conditions, missing permission for the initiating connection is not repaired by adding inbound return-port rules; tracked replies to allowed flows are already permitted. The more specific mechanism is security groups are stateful: replies to an allowed connection are tracked, but a new database connection still needs the initial direction permitted.
D:Stateful inspection tracks connection context rather than evaluating packets entirely independently. That property alone cannot account for the reported symptom; missing permission for the initiating connection is not repaired by adding inbound return-port rules; tracked replies to allowed flows are already permitted.
Question 675
In an AWS networking assessment, an application team stores its private TLS certificate key in the same public code repository as its certificate chain. Which technical explanation BEST accounts for the observed condition?
- AWS Private CA can issue and manage private certificates in a controlled trust hierarchy.
- Private certificates require trust-chain distribution to clients that validate the service.
- Direct Connect dedicated private transport alone does not guarantee confidentiality of application data in transit.
- Private key confidentiality is required regardless of the public visibility of certificate files.
Explanation
Correct Answer
D:Possession of the server private key enables impersonation even when its certificate is public. This explains the observed network behavior, which can be checked by verifying that the leaked key is revoked or replaced and the new key is inaccessible to public repositories.
Incorrect Answers
A:Private PKI establishes internal identity only when clients explicitly trust its CA chain. The decisive technical distinction is private key confidentiality is required regardless of the public visibility of certificate files; possession of the server private key enables impersonation even when its certificate is public.
B:A technically signed certificate is not trusted unless the verifier has the appropriate CA chain. The reported evidence instead concerns private key confidentiality is required regardless of the public visibility of certificate files: possession of the server private key enables impersonation even when its certificate is public.
C:Private routing reduces exposure to public internet paths but does not independently encrypt packet payloads. That property alone cannot account for the reported symptom; possession of the server private key enables impersonation even when its certificate is public.
Question 676
An AWS network engineer must address this specific condition: A CloudFront distribution custom domain uses an ACM certificate provisioned only in a different Region. Which implementation or operational change BEST meets the requirement?
- Request or import the correct matching ACM certificate in us-east-1 for the distribution.
- Require HTTPS-only origin protocol policy and validate origin certificate trust.
- Deploy the correct approved private CA root or intermediate trust to authorized clients.
- Publish the correct parent DS record after enabling the hosted zone's DNSSEC signing.
Explanation
Correct Answer
A:CloudFront's certificate region requirements differ from those of regional ALB listeners. Confirm the change by checking that the distribution accepts the custom certificate and viewers validate the alternate domain.
Incorrect Answers
B:Secure viewer-to-edge traffic does not protect origin traffic when the origin connection remains cleartext. It does not directly achieve the required result: the distribution accepts the custom certificate and viewers validate the alternate domain. The constraint is that CloudFront's certificate region requirements differ from those of regional ALB listeners.
C:A technically signed certificate is not trusted unless the verifier has the appropriate CA chain. That adjustment does not address the controlling condition: CloudFront's certificate region requirements differ from those of regional ALB listeners. Verify the distribution accepts the custom certificate and viewers validate the alternate domain.
D:A signed child zone alone does not prove authenticity to validators without the parent trust chain. In this situation, CloudFront's certificate region requirements differ from those of regional ALB listeners. The proposed change does not ensure the distribution accepts the custom certificate and viewers validate the alternate domain.
Question 677
An AWS network engineer must address this specific condition: A Direct Connect LAG has unequal member configuration and link aggregation does not establish as designed. Which implementation or operational change BEST meets the requirement?
- Make LAG member connections satisfy supported speed, location and configuration requirements.
- Align the customer peer ASN and configured Direct Connect VIF peer settings.
- Associate supported virtual private gateways to the Direct Connect gateway and confirm each prefix scope.
- Update the approved BGP authentication secret consistently on both peering ends.
Explanation
Correct Answer
A:A link aggregation group is not an arbitrary bundle of dissimilar circuits across Regions. Confirm the change by checking that the LAG reports healthy synchronized members with the expected aggregated capacity.
Incorrect Answers
B:An ASN mismatch prevents valid BGP neighbor establishment even with correct VLAN transport. The needed control instead targets Direct Connect LAG membership and port speed or location requirements must be compatible for aggregation; it succeeds when the LAG reports healthy synchronized members with the expected aggregated capacity.
C:A private VIF can terminate at a gateway abstraction without one VIF per VPC when constraints permit. The needed control instead targets Direct Connect LAG membership and port speed or location requirements must be compatible for aggregation; it succeeds when the LAG reports healthy synchronized members with the expected aggregated capacity.
D:BGP peer authentication blocks routing establishment when credentials do not agree. In this situation, a link aggregation group is not an arbitrary bundle of dissimilar circuits across Regions. The proposed change does not ensure the LAG reports healthy synchronized members with the expected aggregated capacity.
Question 678
In an AWS networking assessment, a DNS query log contains repeated NXDOMAIN responses for an internal host that was recently renamed. Which technical explanation BEST accounts for the observed condition?
- CloudWatch alarm missing-data treatment affects state when metric samples are absent.
- Repeated NXDOMAIN answers indicate a missing matching name in the resolver's authoritative view.
- A flow-log ACCEPT does not prove a socket listener or end-to-end application response exists.
- An ALB 504 can reflect a backend timeout even when network routes and listener rules are valid.
Explanation
Correct Answer
B:Changing packet routing cannot create a DNS record that does not exist in the queried zone. This explains the observed network behavior, which can be checked by verifying that the intended name returns the correct A or AAAA record after DNS data repair.
Incorrect Answers
A:No datapoint is not always equivalent to a healthy zero measurement. For the stated conditions, changing packet routing cannot create a DNS record that does not exist in the queried zone. The more specific mechanism is repeated NXDOMAIN answers indicate a missing matching name in the resolver's authoritative view.
C:Network-layer admission can succeed even when the destination application does not accept connections. The reported evidence instead concerns repeated NXDOMAIN answers indicate a missing matching name in the resolver's authoritative view: changing packet routing cannot create a DNS record that does not exist in the queried zone.
D:Load-balancer target timing and application processing can exceed idle or response timeout limits. The reported evidence instead concerns repeated NXDOMAIN answers indicate a missing matching name in the resolver's authoritative view: changing packet routing cannot create a DNS record that does not exist in the queried zone.
Question 679
In an AWS networking assessment, a subnet route table is modified directly after an approved IaC deployment, bypassing standard review. Which technical explanation BEST accounts for the observed condition?
- AWS Config change detection and CloudFormation drift checks can flag out-of-band configuration changes.
- AWS Config can evaluate security-group configuration against a required policy rule.
- CloudTrail management events record supported AWS API operations with actor, time and request context.
- CloudFront standard logs report viewer request metadata for supported distributions.
Explanation
Correct Answer
A:An IaC deployment does not continuously prevent later manual console mutations. This explains the observed network behavior, which can be checked by verifying that the unexpected route modification appears as a configuration change and is corrected.
Incorrect Answers
B:Continuous configuration assessment complements packet monitoring by measuring deployed control state. The decisive technical distinction is AWS Config change detection and CloudFormation drift checks can flag out-of-band configuration changes; an IaC deployment does not continuously prevent later manual console mutations.
C:A management-plane audit trail attributes configuration changes, unlike aggregated data-plane flow records. The reported evidence instead concerns AWS Config change detection and CloudFormation drift checks can flag out-of-band configuration changes: an IaC deployment does not continuously prevent later manual console mutations.
D:Edge delivery requests can bypass origin logs on cache hits, so origin-only auditing is incomplete. The decisive technical distinction is AWS Config change detection and CloudFormation drift checks can flag out-of-band configuration changes; an IaC deployment does not continuously prevent later manual console mutations.
Question 680
In an AWS networking assessment, a Direct Connect gateway is attached to a virtual private gateway and an operator lists a /24 narrower than the VPC /16. Which technical explanation BEST accounts for the observed condition?
- Cross-account Direct Connect gateway associations require proposal and acceptance by the responsible owners.
- For virtual private gateway associations, allowed prefixes filter VPC CIDRs and cannot advertise an unmatched narrower CIDR.
- A transit virtual interface terminates at a Direct Connect gateway associated with Transit Gateways.
- A Direct Connect private virtual interface supports private IP routing toward supported VPC gateway connections.
Explanation
Correct Answer
B:VGW allowed-prefix filters cannot force unsupported more-specific VPC routes to appear in BGP. This explains the observed network behavior, which can be checked by verifying that the corporate router learns the full intended VPC CIDR after correcting the filter.
Incorrect Answers
A:Owning the Transit Gateway does not automatically grant authority to attach another account's Direct Connect gateway. That property alone cannot account for the reported symptom; vGW allowed-prefix filters cannot force unsupported more-specific VPC routes to appear in BGP.
C:Transit VIF connectivity targets Transit Gateway associations instead of directly attaching every individual VPC. The decisive technical distinction is for virtual private gateway associations, allowed prefixes filter VPC CIDRs and cannot advertise an unmatched narrower CIDR; vGW allowed-prefix filters cannot force unsupported more-specific VPC routes to appear in BGP.
D:The virtual interface type determines whether connectivity targets private VPC addresses or public AWS endpoints. The decisive technical distinction is for virtual private gateway associations, allowed prefixes filter VPC CIDRs and cannot advertise an unmatched narrower CIDR; vGW allowed-prefix filters cannot force unsupported more-specific VPC routes to appear in BGP.
AWS Certified Advanced Networking - Specialty ANS-C01 Practice Tests