Question 440 A router interface accepts IPv6 SSH from a maintenance host even though the team configured an IPv4 ACL denying its IPv4 equivalent. Which lasting design or operational safeguard best prevents this particular issue from recurring? Use defined source-address allowlists and do not assume loose uRPF equals strict ingress validation. Use ordered exception reviews and negative tests before ACL deployment. Validate supported syntax and feature matrices before distributing common ACL templates. Review IPv4 and IPv6 filters together in dual-stack hardening checks. ExplanationCorrect Answer D:Review IPv4 and IPv6 filters together in dual-stack hardening checks. This addresses the recurring cause: IPv4 ACLs do not filter IPv6 packets; IPv6 traffic needs separate IPv6 policy and matching syntax. A targeted acceptance check is: Test IPv6 SSH from authorized and unauthorized hosts against IPv6 ACL counters. Other Answers A:Use defined source-address allowlists and do not assume loose uRPF equals strict ingress validation. IPv4 ACLs do not filter IPv6 packets; IPv6 traffic needs separate IPv6 policy and matching syntax. B:Use ordered exception reviews and negative tests before ACL deployment. IPv4 ACLs do not filter IPv6 packets; IPv6 traffic needs separate IPv6 policy and matching syntax. C:Validate supported syntax and feature matrices before distributing common ACL templates. IPv4 ACLs do not filter IPv6 packets; IPv6 traffic needs separate IPv6 policy and matching syntax.
Question 441 A time-based IPv4 ACL should allow overnight backups, but the permit never activates because the router's clock and timezone are wrong. Which corrective action most directly resolves the documented failure without suppressing unrelated safeguards? Correct and synchronize device time and validate the referenced time-range configuration. Add a narrowly scoped permit for the authorized DNS traffic before the implicit deny. Use an appropriately placed extended ACL that matches source, destination and required transport ports. Trace each applied ACL and relevant control-plane policy along the actual packet path rather than expanding the local permit. ExplanationCorrect Answer A:Correct and synchronize device time and validate the referenced time-range configuration. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. Check clock/timezone, active time range and backup traffic at the intended window. Other Answers B:Add a narrowly scoped permit for the authorized DNS traffic before the implicit deny. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. C:Use an appropriately placed extended ACL that matches source, destination and required transport ports. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. D:Trace each applied ACL and relevant control-plane policy along the actual packet path rather than expanding the local permit. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching.
Question 442 A time-based IPv4 ACL should allow overnight backups, but the permit never activates because the router's clock and timezone are wrong. Which technical mechanism best explains the behavior observed in this scenario? Loose uRPF checks that a route to the source exists; a default route may satisfy that criterion depending on implementation settings. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. IPv4 ACLs do not filter IPv6 packets; IPv6 traffic needs separate IPv6 policy and matching syntax. A standard IPv4 ACL matches source addressing only, while extended ACLs can match more packet fields. ExplanationCorrect Answer B:Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. This explains why the initial condition produces the observed failure. The direct repair is: Correct and synchronize device time and validate the referenced time-range configuration. Validate through: Check clock/timezone, active time range and backup traffic at the intended window. Other Answers A:Loose uRPF checks that a route to the source exists; a default route may satisfy that criterion depending on implementation settings. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. C:IPv4 ACLs do not filter IPv6 packets; IPv6 traffic needs separate IPv6 policy and matching syntax. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. D:A standard IPv4 ACL matches source addressing only, while extended ACLs can match more packet fields. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching.
Question 443 A time-based IPv4 ACL should allow overnight backups, but the permit never activates because the router's clock and timezone are wrong. After applying the correction, which verification evidence most directly demonstrates that this issue is resolved? Observe a permitted local ACL hit alongside a deny hit at the actual blocking policy. Inspect ACE hit counts and verify only the intended DNS exchange now passes. Check clock/timezone, active time range and backup traffic at the intended window. Inspect running policy and counters for representative new addresses after deployment. ExplanationCorrect Answer C:Check clock/timezone, active time range and backup traffic at the intended window. This checks the affected traffic or control-plane behavior, not merely a generic up/down indicator. The underlying mechanism is: Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. Other Answers A:Observe a permitted local ACL hit alongside a deny hit at the actual blocking policy. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. B:Inspect ACE hit counts and verify only the intended DNS exchange now passes. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. D:Inspect running policy and counters for representative new addresses after deployment. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching.
Question 444 A time-based IPv4 ACL should allow overnight backups, but the permit never activates because the router's clock and timezone are wrong. Which lasting design or operational safeguard best prevents this particular issue from recurring? Use ordered exception reviews and negative tests before ACL deployment. Validate supported syntax and feature matrices before distributing common ACL templates. Monitor source-prefix reachability alongside ingress anti-spoofing drops. Include time synchronization monitoring for all time-dependent firewall and ACL policies. ExplanationCorrect Answer D:Include time synchronization monitoring for all time-dependent firewall and ACL policies. This addresses the recurring cause: Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. A targeted acceptance check is: Check clock/timezone, active time range and backup traffic at the intended window. Other Answers A:Use ordered exception reviews and negative tests before ACL deployment. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. B:Validate supported syntax and feature matrices before distributing common ACL templates. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. C:Monitor source-prefix reachability alongside ingress anti-spoofing drops. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching.
Question 445 A new edge ACL is attached inbound on the LAN interface, but operators test outbound traffic on a different routed path and see no counter increments. Which corrective action most directly resolves the documented failure without suppressing unrelated safeguards? Verify the actual traffic ingress path and apply the policy to the correct interface and direction. Add a narrowly scoped permit for the authorized DNS traffic before the implicit deny. Trace each applied ACL and relevant control-plane policy along the actual packet path rather than expanding the local permit. Use an appropriately placed extended ACL that matches source, destination and required transport ports. ExplanationCorrect Answer A:Verify the actual traffic ingress path and apply the policy to the correct interface and direction. Interface ACLs inspect packets only as they cross the configured interface in the specified direction. Use packet-path tracing and ACE counters to show the target flow actually encounters the policy. Other Answers B:Add a narrowly scoped permit for the authorized DNS traffic before the implicit deny. Interface ACLs inspect packets only as they cross the configured interface in the specified direction. C:Trace each applied ACL and relevant control-plane policy along the actual packet path rather than expanding the local permit. Interface ACLs inspect packets only as they cross the configured interface in the specified direction. D:Use an appropriately placed extended ACL that matches source, destination and required transport ports. Interface ACLs inspect packets only as they cross the configured interface in the specified direction.
Question 446 A new edge ACL is attached inbound on the LAN interface, but operators test outbound traffic on a different routed path and see no counter increments. Which technical mechanism best explains the behavior observed in this scenario? IPv4 ACLs do not filter IPv6 packets; IPv6 traffic needs separate IPv6 policy and matching syntax. Interface ACLs inspect packets only as they cross the configured interface in the specified direction. Cisco ACL entries are evaluated in order and processing stops at the first match. Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. ExplanationCorrect Answer B:Interface ACLs inspect packets only as they cross the configured interface in the specified direction. This explains why the initial condition produces the observed failure. The direct repair is: Verify the actual traffic ingress path and apply the policy to the correct interface and direction. Validate through: Use packet-path tracing and ACE counters to show the target flow actually encounters the policy. Other Answers A:IPv4 ACLs do not filter IPv6 packets; IPv6 traffic needs separate IPv6 policy and matching syntax. Interface ACLs inspect packets only as they cross the configured interface in the specified direction. C:Cisco ACL entries are evaluated in order and processing stops at the first match. Interface ACLs inspect packets only as they cross the configured interface in the specified direction. D:Time-range ACL evaluation depends on the router's effective time settings as well as packet matching. Interface ACLs inspect packets only as they cross the configured interface in the specified direction.
Question 447 A new edge ACL is attached inbound on the LAN interface, but operators test outbound traffic on a different routed path and see no counter increments. After applying the correction, which verification evidence most directly demonstrates that this issue is resolved? Inspect running policy and counters for representative new addresses after deployment. Observe a permitted local ACL hit alongside a deny hit at the actual blocking policy. Use packet-path tracing and ACE counters to show the target flow actually encounters the policy. Inspect hit counters for the deny and permit ACEs and test HTTPS plus denied non-HTTPS traffic. ExplanationCorrect Answer C:Use packet-path tracing and ACE counters to show the target flow actually encounters the policy. This checks the affected traffic or control-plane behavior, not merely a generic up/down indicator. The underlying mechanism is: Interface ACLs inspect packets only as they cross the configured interface in the specified direction. Other Answers A:Inspect running policy and counters for representative new addresses after deployment. Interface ACLs inspect packets only as they cross the configured interface in the specified direction. B:Observe a permitted local ACL hit alongside a deny hit at the actual blocking policy. Interface ACLs inspect packets only as they cross the configured interface in the specified direction. D:Inspect hit counters for the deny and permit ACEs and test HTTPS plus denied non-HTTPS traffic. Interface ACLs inspect packets only as they cross the configured interface in the specified direction.
Question 448 A new edge ACL is attached inbound on the LAN interface, but operators test outbound traffic on a different routed path and see no counter increments. Which lasting design or operational safeguard best prevents this particular issue from recurring? Choose ACL type and placement according to the fields required by the security decision. Maintain end-to-end access path diagrams and test overlapping controls together. Monitor source-prefix reachability alongside ingress anti-spoofing drops. Map interface/direction placement to forwarding paths during every ACL change. ExplanationCorrect Answer D:Map interface/direction placement to forwarding paths during every ACL change. This addresses the recurring cause: Interface ACLs inspect packets only as they cross the configured interface in the specified direction. A targeted acceptance check is: Use packet-path tracing and ACE counters to show the target flow actually encounters the policy. Other Answers A:Choose ACL type and placement according to the fields required by the security decision. Interface ACLs inspect packets only as they cross the configured interface in the specified direction. B:Maintain end-to-end access path diagrams and test overlapping controls together. Interface ACLs inspect packets only as they cross the configured interface in the specified direction. C:Monitor source-prefix reachability alongside ingress anti-spoofing drops. Interface ACLs inspect packets only as they cross the configured interface in the specified direction.
Question 449 An extended ACL with a permit for TCP destination port 22 cannot pass SSH because another policy earlier on the path denies the same connection. Which corrective action most directly resolves the documented failure without suppressing unrelated safeguards? Trace each applied ACL and relevant control-plane policy along the actual packet path rather than expanding the local permit. Move the specific permit ahead of the matching deny while keeping the rest of the ACL's policy intact. Apply a properly scoped IPv6 traffic-filter policy to the correct interface and direction. Add a narrowly scoped permit for the authorized DNS traffic before the implicit deny. ExplanationCorrect Answer A:Trace each applied ACL and relevant control-plane policy along the actual packet path rather than expanding the local permit. An interface ACL permit does not override a deny at a different processing point or security layer. Observe a permitted local ACL hit alongside a deny hit at the actual blocking policy. Other Answers B:Move the specific permit ahead of the matching deny while keeping the rest of the ACL's policy intact. An interface ACL permit does not override a deny at a different processing point or security layer. C:Apply a properly scoped IPv6 traffic-filter policy to the correct interface and direction. An interface ACL permit does not override a deny at a different processing point or security layer. D:Add a narrowly scoped permit for the authorized DNS traffic before the implicit deny. An interface ACL permit does not override a deny at a different processing point or security layer.
Question 450 An extended ACL with a permit for TCP destination port 22 cannot pass SSH because another policy earlier on the path denies the same connection. Which technical mechanism best explains the behavior observed in this scenario? Interface ACLs inspect packets only as they cross the configured interface in the specified direction. An interface ACL permit does not override a deny at a different processing point or security layer. ACL object-group support and expansion depend on platform and software; unsupported constructs do not create intended matches. uRPF depends on source-route lookup; losing a legitimate source route can make valid traffic fail reverse-path checks. ExplanationCorrect Answer B:An interface ACL permit does not override a deny at a different processing point or security layer. This explains why the initial condition produces the observed failure. The direct repair is: Trace each applied ACL and relevant control-plane policy along the actual packet path rather than expanding the local permit. Validate through: Observe a permitted local ACL hit alongside a deny hit at the actual blocking policy. Other Answers A:Interface ACLs inspect packets only as they cross the configured interface in the specified direction. An interface ACL permit does not override a deny at a different processing point or security layer. C:ACL object-group support and expansion depend on platform and software; unsupported constructs do not create intended matches. An interface ACL permit does not override a deny at a different processing point or security layer. D:URPF depends on source-route lookup; losing a legitimate source route can make valid traffic fail reverse-path checks. An interface ACL permit does not override a deny at a different processing point or security layer.
