Question 850

An operations report compares traffic charges between AZs but lacks any evidence of the network volume flowing between deployment tiers. Which telemetry should be correlated with billing?

  1. Configure VPC Traffic Mirroring from the supported source ENI to an inspection target
  2. Verify the VPC Flow Logs resource scope, traffic type, and aggregation interval
  3. Explain that VPC Flow Logs aggregate connection metadata and do not uniquely represent individual HTTP transactions
  4. Analyze VPC Flow Logs and application network metrics alongside Cost Explorer usage

Explanation

Correct Answer

D:

Flow logs and workload metrics can identify traffic patterns responsible for transfer charges, while Cost Explorer records the billing dimensions needed to prioritize optimizations.

Incorrect Answers

A:

Traffic Mirroring copies selected packets so the analyzer can inspect protocol exchanges; VPC Flow Logs record connection metadata rather than full packet payload; the operational gap would remain because the question requires a way to link cross-AZ traffic patterns to cost.

B:

Flow Logs aggregate network-flow information over a time window and only cover selected ENIs, subnets, or VPCs; request logs and flow records are not guaranteed one-to-one; it is not the action that directly makes the system link cross-AZ traffic patterns to cost.

C:

HTTP requests may share TCP connections, and flow aggregation produces network records rather than one request row, so different record counts do not inherently mean loss; that still would not establish the requested outcome: link cross-AZ traffic patterns to cost.

Question 851

A networking team wants to report CloudFront cache-hit effectiveness separately from application origin 5xx errors. Which collection design preserves that distinction?

  1. Remove irrelevant request dimensions from the CloudFront cache key and test object correctness
  2. Monitor CloudFront cache statistics and origin error metrics in separate CloudWatch dashboards
  3. Switch to the S3 REST bucket origin and use CloudFront origin access control with a restrictive bucket policy
  4. The cache key includes unnecessary query strings, fragmenting otherwise reusable objects

Explanation

Correct Answer

B:

Edge hit rates describe cache behavior, whereas origin errors diagnose backend responses; combining them as one success percentage obscures different failure causes.

Incorrect Answers

A:

Smaller cache-key cardinality improves reuse of an unchanged representation; security-sensitive or response-varying fields must remain properly isolated to avoid mixing distinct content; it is not the action that directly makes the system distinguish cache efficiency from origin failures.

C:

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; the scenario instead needs an action that will distinguish cache efficiency from origin failures.

D:

If irrelevant tracking parameters form separate cache keys, edge caches store many variants even when origin content is identical, reducing cache-hit ratio; those conditions do not produce the required result: distinguish cache efficiency from origin failures.

Question 852

An ECS service replaces tasks frequently and each replacement receives a new private IP. Other workloads need an internal DNS name that tracks currently registered task endpoints without manually editing Route 53 records. Which design fits?

  1. Register all task IPs permanently in a static public hosted zone
  2. Create a separate NAT gateway for every task to stabilize its network identity
  3. Use AWS Cloud Map service discovery integrated with ECS service registrations
  4. Increase the TTL of a manually maintained A record to one day

Explanation

Correct Answer

C:

ECS can register and deregister healthy task endpoints through AWS Cloud Map service discovery, allowing clients to resolve a name that follows the service's task lifecycle.

Incorrect Answers

A:

A static list would retain decommissioned task addresses and expose names through public DNS when the request is for internal service discovery.

B:

NAT gateways provide egress translation and do not give each changing ECS task a stable inbound private endpoint.

D:

A longer TTL prolongs stale cached addresses and worsens the effect of task churn rather than automate endpoint registration.

Question 853

A branch router receives a Direct Connect private VIF route for a corporate network but Internet-bound traffic must continue using its existing ISP. What BGP design minimizes accidental default-route attraction?

  1. Create separately configured virtual interfaces with their own VLAN and BGP session parameters
  2. Advertise only the intended private prefixes over the Direct Connect BGP session
  3. Investigate optical signal health, patching, and physical circuit errors on the affected DX path
  4. Match the customer router BGP ASN to the customer ASN configured on the Direct Connect VIF

Explanation

Correct Answer

B:

Restricting advertised prefixes keeps hybrid routing within the intended enterprise reachability boundary; unnecessary default route advertisements can attract traffic not meant for Direct Connect.

Incorrect Answers

A:

Each VIF provides a distinct routed VLAN/BGP context over the eligible physical connection; it does not create independent physical redundancy; the scenario instead needs an action that will limit BGP-learned routes to private prefixes.

C:

Optical light or error alarms indicate a physical transport issue; BGP resets can be a downstream symptom rather than evidence that route selection needs tuning; it changes a different aspect of the architecture rather than fulfilling the need to limit BGP-learned routes to private prefixes.

D:

BGP neighbors must agree on each other's peer ASNs; a functioning physical circuit and VLAN cannot establish the control-plane adjacency when the remote AS is configured incorrectly; the operational gap would remain because the question requires a way to limit BGP-learned routes to private prefixes.

Question 854

An enterprise needs highly available private connectivity from two independent colocation sites, with on-premises failure-domain separation. Which plan is strongest?

  1. Use transit VIFs, a Direct Connect gateway, and associated Transit Gateways
  2. Set the LAG minimum link count to the required number of healthy members
  3. Provision Direct Connect connections in separate locations with independent customer-side routing infrastructure
  4. Create separately configured virtual interfaces with their own VLAN and BGP session parameters

Explanation

Correct Answer

C:

Distinct physical facilities and routers reduce correlated outages; multiple VLANs or VIFs on one physical circuit do not create separate transport failure domains.

Incorrect Answers

A:

A Direct Connect gateway can connect eligible transit virtual interfaces to TGWs across supported Regions, avoiding a separate VIF per individual VPC; those conditions do not produce the required result: survive a single Direct Connect facility failure.

B:

The minimum-links setting makes the aggregated connection unavailable when fewer than the configured number of physical links remain, preventing operation below the chosen physical redundancy threshold; it changes a different aspect of the architecture rather than fulfilling the need to survive a single Direct Connect facility failure.

D:

Each VIF provides a distinct routed VLAN/BGP context over the eligible physical connection; it does not create independent physical redundancy; it is not the action that directly makes the system survive a single Direct Connect facility failure.

Question 855

A company wants a shared Direct Connect entry to connect on-premises routers to several AWS Regions through regional Transit Gateways. Which gateway combination supports centralized routing?

  1. Use transit VIFs, a Direct Connect gateway, and associated Transit Gateways
  2. Use a Direct Connect public virtual interface for supported public AWS endpoints
  3. Update the Direct Connect gateway association's allowed prefixes for the intended TGW routes
  4. Configure MACsec on a supported Direct Connect dedicated connection and compatible customer hardware

Explanation

Correct Answer

A:

A Direct Connect gateway can connect eligible transit virtual interfaces to TGWs across supported Regions, avoiding a separate VIF per individual VPC.

Incorrect Answers

B:

Public VIFs exchange public AWS service prefixes and customer public addressing, unlike transit VIFs, which carry hybrid private routes toward TGWs; the operational gap would remain because the question requires a way to attach multiple regional TGWs to hybrid ingress.

C:

The allowed-prefix configuration controls which connected AWS-side ranges are advertised toward on-premises through this association; it is not a generic subnet route table entry; it is not the action that directly makes the system attach multiple regional TGWs to hybrid ingress.

D:

MACsec protects Ethernet frames on eligible Direct Connect physical links, subject to connection speed, location, and equipment support; it does not replace application-layer encryption throughout the AWS service path; that still would not establish the requested outcome: attach multiple regional TGWs to hybrid ingress.

Question 856

An enterprise needs encrypted backup connectivity if its primary dedicated private Direct Connect path fails. Which independent logical service should be designed?

  1. Establish BGP over a dynamic-routing Site-to-Site VPN connection
  2. Configure and monitor both VPN tunnel interfaces and BGP neighbors on the customer gateway
  3. Attach a Site-to-Site VPN to Transit Gateway and establish BGP tunnels with the customer gateway
  4. Deploy AWS Site-to-Site VPN as a secondary encrypted path with appropriate BGP preferences

Explanation

Correct Answer

D:

A VPN can use an internet or supported private underlay as an alternate route, while BGP can prefer Direct Connect until failure occurs; the physical independence of the backup still matters.

Incorrect Answers

A:

BGP exchanges prefixes and responds to route withdrawals across the VPN tunnel; static routing requires explicit configuration and does not provide equivalent dynamic route signaling; the operational gap would remain because the question requires a way to provide encrypted failover for hybrid links.

B:

AWS provides two tunnels for redundancy; leaving a second tunnel's routing session unconfigured prevents it from taking over during planned or unplanned maintenance; it is not the action that directly makes the system provide encrypted failover for hybrid links.

C:

TGW VPN attachments connect encrypted on-premises tunnels to transit route tables, which must also contain the routes and attachment policies for reachable VPC prefixes; that still would not establish the requested outcome: provide encrypted failover for hybrid links.

Question 857

A transit VIF is proposed for accessing a single public AWS service endpoint rather than private network prefixes. What VIF type actually provides public AWS address reachability?

  1. Accept the hosted connection in the intended AWS account before creating the virtual interface
  2. Use an approved encryption layer such as IPsec over the DX transport where required
  3. Update the Direct Connect gateway association's allowed prefixes for the intended TGW routes
  4. Use a Direct Connect public virtual interface for supported public AWS endpoints

Explanation

Correct Answer

D:

Public VIFs exchange public AWS service prefixes and customer public addressing, unlike transit VIFs, which carry hybrid private routes toward TGWs.

Incorrect Answers

A:

Hosted connections require the recipient to accept the provisioned connection; only after acceptance can the account configure the supported VIF and start routing; it is not the action that directly makes the system reach public AWS services over DX.

B:

A private DX connection supplies dedicated network connectivity but does not inherently guarantee end-to-end payload encryption for all services; overlay encryption must be deliberately deployed when needed; that still would not establish the requested outcome: reach public AWS services over DX.

C:

The allowed-prefix configuration controls which connected AWS-side ranges are advertised toward on-premises through this association; it is not a generic subnet route table entry; the scenario instead needs an action that will reach public AWS services over DX.

Question 858

An on-premises router and AWS VPN peer must learn customer prefixes dynamically and withdraw failed paths without manual static route changes. Which routing protocol is appropriate?

  1. Establish BGP over a dynamic-routing Site-to-Site VPN connection
  2. Configure BGP using the inside tunnel addresses and AWS peer ASN supplied for that VPN tunnel
  3. Attach a Site-to-Site VPN to Transit Gateway and establish BGP tunnels with the customer gateway
  4. Configure and monitor both VPN tunnel interfaces and BGP neighbors on the customer gateway

Explanation

Correct Answer

A:

BGP exchanges prefixes and responds to route withdrawals across the VPN tunnel; static routing requires explicit configuration and does not provide equivalent dynamic route signaling.

Incorrect Answers

B:

IPsec tunnel establishment authenticates the encrypted underlay; dynamic route exchange requires a separate BGP session with the correct neighbors and ASN over the tunnel interfaces; the scenario instead needs an action that will exchange dynamic routes across IPsec VPN.

C:

TGW VPN attachments connect encrypted on-premises tunnels to transit route tables, which must also contain the routes and attachment policies for reachable VPC prefixes; those conditions do not produce the required result: exchange dynamic routes across IPsec VPN.

D:

AWS provides two tunnels for redundancy; leaving a second tunnel's routing session unconfigured prevents it from taking over during planned or unplanned maintenance; it changes a different aspect of the architecture rather than fulfilling the need to exchange dynamic routes across IPsec VPN.

Question 859

A security appliance needs jumbo frames across a hybrid link; a standard VPN tunnel has additional encapsulation overhead. What design concern must be included?

  1. Measure effective path MTU and adjust TCP MSS or packet size to avoid tunnel fragmentation
  2. Inspect NAT gateway connection and port-allocation metrics for the specific destination tuple
  3. Reuse application TCP connections or distribute destination tuples and NAT source addresses where feasible
  4. Clamp TCP MSS to a value compatible with the smallest encapsulated path MTU

Explanation

Correct Answer

A:

IPsec encapsulation reduces usable payload compared with an unencapsulated Ethernet path, and path MTU/MSS settings help prevent black-holed large packets.

Incorrect Answers

B:

Source port allocation is finite for each NAT gateway address and destination tuple; connection errors under concentrated load can occur before ordinary bandwidth limits are reached; those conditions do not produce the required result: accommodate hybrid encapsulation overhead.

C:

Reducing churn and spreading simultaneous destination flows can mitigate per-tuple ephemeral-port pressure; simply adding unrelated DNS records does not create more NAT port capacity; it changes a different aspect of the architecture rather than fulfilling the need to accommodate hybrid encapsulation overhead.

D:

A successful handshake uses small packets; oversized encrypted data packets may be fragmented or dropped, so an appropriately sized MSS avoids black-hole behavior along the limiting hop; the operational gap would remain because the question requires a way to accommodate hybrid encapsulation overhead.

Question 860

A bank requires separate BGP routing policy for two business units using one supported physical Direct Connect connection. Which logical constructs provide independent sessions?

  1. Create separately configured virtual interfaces with their own VLAN and BGP session parameters
  2. Advertise only the intended private prefixes over the Direct Connect BGP session
  3. Provision Direct Connect connections in separate locations with independent customer-side routing infrastructure
  4. Match the customer router BGP ASN to the customer ASN configured on the Direct Connect VIF

Explanation

Correct Answer

A:

Each VIF provides a distinct routed VLAN/BGP context over the eligible physical connection; it does not create independent physical redundancy.

Incorrect Answers

B:

Restricting advertised prefixes keeps hybrid routing within the intended enterprise reachability boundary; unnecessary default route advertisements can attract traffic not meant for Direct Connect; it changes a different aspect of the architecture rather than fulfilling the need to isolate BGP sessions on a shared physical link.

C:

Distinct physical facilities and routers reduce correlated outages; multiple VLANs or VIFs on one physical circuit do not create separate transport failure domains; the operational gap would remain because the question requires a way to isolate BGP sessions on a shared physical link.

D:

BGP neighbors must agree on each other's peer ASNs; a functioning physical circuit and VLAN cannot establish the control-plane adjacency when the remote AS is configured incorrectly; it is not the action that directly makes the system isolate BGP sessions on a shared physical link.

AWS Certified Advanced Networking - Specialty ANS-C01 Practice Tests