Question 810
A manufacturer has private or transit Direct Connect virtual interfaces in two separated locations, both connected to its Direct Connect gateway. It wants traffic to travel directly between the two on-premises locations over AWS's backbone without detouring through a VPC in a Region. What feature should be enabled?
- Configure a public VIF only and expect all private site-to-site prefixes to traverse it
- Create a VPC NAT gateway in one Region to relay all on-premises traffic
- Add a Route 53 weighted record for each data center router's private address
- Enable AWS Direct Connect SiteLink on the eligible virtual interfaces at both locations
Explanation
Correct Answer
D:SiteLink permits private site-to-site traffic between eligible Direct Connect locations over the AWS network while avoiding a transit through an AWS Region. The enabled virtual interfaces must participate in the Direct Connect gateway design.
Incorrect Answers
A:Public VIFs are for AWS public endpoint routing, not SiteLink's private or transit virtual-interface path. A public VIF alone does not implement the requested private branch-to-branch connectivity.
B:A NAT gateway translates outbound traffic from supported VPC subnets and is not a substitute for the Direct Connect SiteLink branch-to-branch backbone path.
C:DNS record weighting influences client name resolution, not direct BGP route exchange or the network path between on-premises Direct Connect locations.
Question 811
A distributed compute application requires low-latency message passing and high-throughput inter-node communication. Which change is the most appropriate?
- Place the cluster in a cluster placement group when supported
- Enable and verify ENA support and drivers on a compatible instance
- Profile packet rate and use suitable instance networking capabilities with ENA
- Select supported EC2 instances with Elastic Fabric Adapter and appropriate placement
- Attach multiple compatible elastic network interfaces to the EC2 instance
Explanation
Correct Answer
D:This configuration supports optimized HPC communication patterns with an EFA network interface; an ordinary ENI offers baseline networking but not the EFA communication path, so it delivers tightly coupled cluster networking performance under the stated constraints.
Incorrect Answers
A:Although this setting co-locates eligible instances to optimize low-latency network communication, spread placement distributes instances to distinct hardware and serves a different goal; this concerns tightly placed single-AZ compute networking, not the specified tightly coupled cluster networking performance.
B:The proposed action uses enhanced networking capabilities for higher packet-processing performance; increasing a subnet CIDR does not change instance network driver capability, supporting improved EC2 packet throughput and latency but leaving tightly coupled cluster networking performance unmet.
C:This approach considers packet-per-second limits and accelerated I/O efficiency; raw advertised gigabits per second do not describe every small-packet workload limit, which helps with higher sustainable EC2 packet-processing rate instead of delivering tightly coupled cluster networking performance.
E:Although this setting presents separate interface identities, addresses and security group attachments, placement group settings do not create additional logical interfaces; this concerns multi-homed EC2 appliance connectivity, not the specified tightly coupled cluster networking performance.
Question 812
An NLB routes too much load to one AZ while targets are spread across enabled zones and zonal distribution is undesirable. What should the network specialist configure?
- Create an NLB TLS listener with the appropriate certificate
- Enable Proxy Protocol v2 and configure the application to parse its header
- Enable cross-zone load balancing after evaluating costs and requirements
- Allocate Elastic IP addresses to an internet-facing Network Load Balancer where supported
Explanation
Correct Answer
C:This configuration permits load-balancer nodes to distribute requests to healthy targets in other enabled AZs; availability-zone affinity and possible data processing charges should be examined, so it delivers cross-zone target utilization under the stated constraints.
Incorrect Answers
A:This alternative performs TLS termination at the network load balancer before forwarding to its target group; a raw TCP listener would normally pass encrypted bytes to the targets, so it addresses managed transport-layer TLS offload rather than the required cross-zone target utilization.
B:Although this setting conveys source-connection metadata to compatible targets before the application payload, this requires target support and must account for health-check connections; this concerns delivery of original client metadata to backend software, not the specified cross-zone target utilization.
D:This approach provides stable public IP addressing for NLB zonal nodes; an ALB DNS name can change node IP addresses and is not configured with Elastic IPs, which helps with zonal fixed-address TCP ingress instead of delivering cross-zone target utilization.
Question 813
A partner must connect to an internal service privately from its AWS account rather than using public internet ingress. What should the network specialist configure?
- Integrate an ALB HTTPS listener with AWS WAF and private target groups
- Place the application behind an approved identity-aware access proxy or VPN
- Create an inbound database security-group rule referencing the application security group
- Apply appropriate NLB security-group and backend network controls where supported
- Expose the service through PrivateLink endpoint-service access
- Combine supported AWS Shield protections with WAF at the eligible web entry points
Explanation
Correct Answer
E:This configuration creates an approved private interface endpoint path from consumer VPCs; an internet-facing ALB would still expose a public endpoint, so it delivers partner-specific private application ingress under the stated constraints.
Incorrect Answers
A:This approach combines layer-seven TLS ingress and web request filtering before backend forwarding; exposing the backend instances directly would bypass the web front door, which helps with layered HTTP perimeter protection for private applications instead of delivering partner-specific private application ingress.
B:This alternative requires authenticated access before sensitive network endpoints are reachable; allowing the entire internet CIDR through a security group does not meet access control intent, so it addresses authenticated administrative ingress isolation rather than the required partner-specific private application ingress.
C:Although this setting authorizes stateful source membership rather than an entire shifting address range, security group references avoid maintaining fixed instance IP lists; this concerns narrowly scoped database access from application instances, not the specified partner-specific private application ingress.
D:The proposed action limits permitted transport connections according to source network policy; WAF is not natively an arbitrary TCP payload firewall for an NLB, supporting restricted layer-four public ingress but leaving partner-specific private application ingress unmet.
F:This alternative applies complementary network-scale and HTTP request threat mitigations; a single subnet ACL cannot inspect both global floods and web attack signatures, so it addresses layered perimeter resilience for public services rather than the required partner-specific private application ingress.
Question 814
An operations dashboard needs low-friction alerting on VPC flow records by using CloudWatch Logs filters. What should the network specialist configure?
- Inspect the ACCEPT and REJECT actions in VPC Flow Log records
- Send VPC Flow Logs to CloudWatch Logs
- Enable VPC Flow Logs at the VPC scope
- Deliver VPC Flow Logs to Amazon S3 in a suitable format
Explanation
Correct Answer
B:With this choice, the selected action delivers flow metadata to log groups that support filters and analytics; logging to an S3 bucket alone will not create CloudWatch Logs filter events, providing flow-data integration with CloudWatch log analysis for the network described.
Incorrect Answers
A:The proposed action identifies whether captured network flows were allowed or denied by network controls; flow logs do not reveal application payload content or every packet-level failure cause, supporting reachability evidence at flow-record granularity but leaving flow-data integration with CloudWatch log analysis unmet.
C:This alternative records selected flow metadata for supported network interfaces across the VPC; a subnet-only log would miss interfaces outside the chosen subnet, so it addresses broad IP-flow visibility over changing workloads rather than the required flow-data integration with CloudWatch log analysis.
D:Although this setting stores flow-log records in an object store suitable for later analysis, CloudWatch alarms can analyze metrics but are not an object-archive delivery substitute; this concerns durable searchable flow records in S3, not the specified flow-data integration with CloudWatch log analysis.
Question 815
An AWS Network Firewall stateless rule matches inbound TCP connections to port 22 from a blocked network. Other packets must continue to the stateful inspection engine, but these matched packets must be rejected immediately. Which rule action meets the requirement?
- Apply the stateless DROP action to the matching rule, with a suitable rule priority
- Use the stateless PASS action and rely on the stateful engine to reconsider the same packet
- Use stateless FORWARD_TO_STATEFUL and assume the stateful engine implicitly denies all traffic
- Configure a CloudWatch dashboard without a traffic-enforcement rule
Explanation
Correct Answer
A:In AWS Network Firewall, a matching stateless DROP action stops further inspection and discards the packet. Other packets can follow the policy's forward-to-stateful default, preserving full stateful analysis for traffic not matching this deny rule.
Incorrect Answers
B:Stateless PASS immediately permits the matching packet without sending it to the stateful rules engine. That is the opposite of an immediate deny for the blocked SSH source range.
C:FORWARD_TO_STATEFUL delegates inspection rather than dropping the packet at the stateless stage. A stateful policy may allow flows unless corresponding deny rules are defined, so forwarding does not guarantee the requested immediate reject.
D:CloudWatch dashboards can display firewall metrics but do not enforce policy on packets. Observability alone would leave the disallowed connections subject to whatever current firewall actions apply.
Question 816
An ACM public certificate request has completed domain ownership validation but fails with a Certification Authority Authorization error. The domain has a CAA issue record permitting only an unrelated certificate authority. What should the DNS administrator correct?
- Update the applicable CAA authorization so an Amazon-supported CA can issue the requested ACM public certificate, then retry issuance
- Add a TLSA record only and leave the restrictive CAA rule in place
- Change the load balancer's target health-check threshold to one
- Disable Route 53 Resolver DNSSEC validation inside an unrelated VPC
Explanation
Correct Answer
A:CAA issue records constrain which certificate authorities may issue certificates for a domain. ACM needs a permitted Amazon CA issuer value when restrictive CAA records are present; changing the appropriate record resolves the authorization conflict.
Incorrect Answers
B:A TLSA record expresses DANE-related certificate associations and does not override DNS CAA restrictions used in public CA issuance decisions. ACM could remain blocked by the CAA policy.
C:Target health check thresholds affect backend reachability status after deployment and do not determine which public certificate authorities are authorized by the domain's CAA records.
D:A VPC's recursive DNSSEC validation setting is not the authoritative CAA permission for this public domain. Disabling validation is unrelated to the certificate issuance rejection.
Question 817
A DNS administrator must replace a CNAME at www.example.com with an alias A record, without ever publishing both record types for the same name. How should the Route 53 change be submitted?
- Create the alias record first, then delete the CNAME in a second request
- Delete the entire public hosted zone and create a replacement
- Submit one ChangeResourceRecordSets batch that deletes the CNAME and creates the alias
- Use a latency routing policy so the CNAME and A record can coexist
Explanation
Correct Answer
C:Route 53 validates a change batch transactionally and applies all its changes or none. A delete-and-create batch avoids a partially applied DNS configuration.
Incorrect Answers
A:A CNAME conflicts with other record types at the same owner name; trying to create the alias first does not provide an atomic transition.
B:Deleting the hosted zone disrupts its other records and delegation. A record-type change does not require reconstructing the zone.
D:Latency routing chooses among records of compatible types; it cannot make a CNAME coexist with an A record for the identical name.
Question 818
A broadcaster needs individual CloudFront request records delivered within seconds so an incident detector can react before conventional access-log batches arrive. Which logging capability is appropriate?
- Request or import the CloudFront viewer certificate in US East (N. Virginia)
- Issue CloudFront signed URLs with per-request expiration and signature validation
- Configure CloudFront real-time logs and a Kinesis Data Streams destination
- Switch to the S3 REST bucket origin and use CloudFront origin access control with a restrictive bucket policy
Explanation
Correct Answer
C:Real-time logs stream selected fields from edge requests through Kinesis with configurable sampling; standard access logs are delivered asynchronously and are not designed for low-latency event processing.
Incorrect Answers
A:CloudFront custom viewer certificates managed by ACM are sourced from us-east-1 even if the distribution's origins and application workloads run elsewhere; those conditions do not produce the required result: obtain near-real-time edge request telemetry.
B:A signed URL cryptographically restricts access to a specific resource and validity interval; CloudFront evaluates the signature before serving protected content from its cache; it changes a different aspect of the architecture rather than fulfilling the need to obtain near-real-time edge request telemetry.
D:S3 website endpoints are custom HTTP origins and do not support OAC; the regional REST endpoint can accept CloudFront-signed origin requests while public S3 access remains blocked; it is not the action that directly makes the system obtain near-real-time edge request telemetry.
Question 819
A company delegates example.com to self-hosted authoritative servers named ns1.example.com and ns2.example.com. External resolvers cannot discover the server IPs because the server names are inside the delegated domain. What is missing at the registrar?
- A TXT ownership verification record for every application hostname
- Glue host records with the authoritative servers' IP addresses, alongside the proper NS delegation
- A Route 53 Resolver outbound endpoint for public recursive queries
- A separate MX record for each authoritative name server
Explanation
Correct Answer
B:In-bailiwick name servers need address information available from the parent registry or registrar. Glue records allow iterative resolvers to contact the authoritative servers rather than follow a circular dependency.
Incorrect Answers
A:TXT records can prove ownership for certain services but cannot break the DNS dependency when a delegated zone's name servers are named within that same zone.
C:Private Resolver outbound endpoints forward queries from VPCs and cannot repair internet-wide public-domain delegation glue.
D:MX records designate mail exchangers for the domain and have no role in locating the authoritative DNS name servers. The resolver still needs appropriate parent-side glue addresses for in-bailiwick name servers.
Question 820
A global game relay uses AWS Global Accelerator and requires packets in the same established TCP flow to continue reaching the selected endpoint. What property prevents midflow destination changes?
- Add outbound endpoint IP addresses in subnets across at least two supported Availability Zones
- Rely on flow hashing and endpoint affinity within the standard accelerator
- Restrict endpoint-service allowed principals and require acceptance when appropriate
- Ensure endpoint health checks reflect the application's readiness rather than mere port reachability
Explanation
Correct Answer
B:Global Accelerator consistently maps packets belonging to an established flow to the selected endpoint; traffic dial changes do not arbitrarily split an existing transport flow across endpoints.
Incorrect Answers
A:Multiple subnet IPs in different AZs reduce dependence on a single AZ for DNS forwarding toward on-premises resolvers; redundant target resolvers should also be reachable; the operational gap would remain because the question requires a way to preserve transport-flow endpoint consistency.
C:Endpoint-service permissions control which principals can request interface endpoints, while connection acceptance lets the provider approve eligible consumers before traffic flows; that still would not establish the requested outcome: preserve transport-flow endpoint consistency.
D:Health-based routing is only as meaningful as the endpoint health signal; a basic open TCP listener can remain available while application dependencies fail; the scenario instead needs an action that will preserve transport-flow endpoint consistency.