Question 420 After a TACACS+ server migration, the router sends requests from a new source interface that is not registered as a client on the AAA server. Which lasting design or operational safeguard best prevents this particular issue from recurring? Align administrative AAA protocol choice to required command authorization and audit granularity. Rotate AAA secrets as coordinated server/client changes with rollback and verification. Require accounting acceptance tests independently of authentication during access-control rollout. Standardize stable AAA source-interface addresses and register them before cutover. ExplanationCorrect Answer D:Standardize stable AAA source-interface addresses and register them before cutover. This addresses the recurring cause: AAA servers commonly bind allowed network devices and shared secrets to the packet source address. A targeted acceptance check is: Capture request source IP and confirm the server recognizes it and returns valid responses. Other Answers A:Align administrative AAA protocol choice to required command authorization and audit granularity. AAA servers commonly bind allowed network devices and shared secrets to the packet source address. B:Rotate AAA secrets as coordinated server/client changes with rollback and verification. AAA servers commonly bind allowed network devices and shared secrets to the packet source address. C:Require accounting acceptance tests independently of authentication during access-control rollout. AAA servers commonly bind allowed network devices and shared secrets to the packet source address.
Question 421 Remote AAA authentication works, but no administrator session start/stop records appear after a new accounting policy was deployed. Which corrective action most directly resolves the documented failure without suppressing unrelated safeguards? Apply the appropriate AAA accounting method list to the intended service or line and check server logging. Use a supported TACACS+ command-accounting design for granular device administration events. Synchronize the RADIUS client/server secret and confirm correct source identity and UDP transport. Configure the intended `aaa authorization exec` behavior and validate privilege assignment separately from authentication. ExplanationCorrect Answer A:Apply the appropriate AAA accounting method list to the intended service or line and check server logging. Authentication success does not automatically generate configured accounting records without an accounting method in scope. Verify matched login, logout and accounting session records for one controlled test administrator. Other Answers B:Use a supported TACACS+ command-accounting design for granular device administration events. Authentication success does not automatically generate configured accounting records without an accounting method in scope. C:Synchronize the RADIUS client/server secret and confirm correct source identity and UDP transport. Authentication success does not automatically generate configured accounting records without an accounting method in scope. D:Configure the intended `aaa authorization exec` behavior and validate privilege assignment separately from authentication. Authentication success does not automatically generate configured accounting records without an accounting method in scope.
Question 422 Remote AAA authentication works, but no administrator session start/stop records appear after a new accounting policy was deployed. Which technical mechanism best explains the behavior observed in this scenario? AAA method-list fallback depends on configured methods and usable local credentials when the remote server is unavailable. Authentication success does not automatically generate configured accounting records without an accounting method in scope. Authentication verifies identity, whereas TACACS+ authorization can decide whether a requested CLI command is permitted. AAA named method lists affect only access lines or services to which they are actually applied. ExplanationCorrect Answer B:Authentication success does not automatically generate configured accounting records without an accounting method in scope. This explains why the initial condition produces the observed failure. The direct repair is: Apply the appropriate AAA accounting method list to the intended service or line and check server logging. Validate through: Verify matched login, logout and accounting session records for one controlled test administrator. Other Answers A:AAA method-list fallback depends on configured methods and usable local credentials when the remote server is unavailable. Authentication success does not automatically generate configured accounting records without an accounting method in scope. C:Authentication verifies identity, whereas TACACS+ authorization can decide whether a requested CLI command is permitted. Authentication success does not automatically generate configured accounting records without an accounting method in scope. D:AAA named method lists affect only access lines or services to which they are actually applied. Authentication success does not automatically generate configured accounting records without an accounting method in scope.
Question 423 Remote AAA authentication works, but no administrator session start/stop records appear after a new accounting policy was deployed. After applying the correction, which verification evidence most directly demonstrates that this issue is resolved? Compare authenticated identity with EXEC privilege and authorization traces on test accounts. Show server accounting records containing administrator identities and executed commands. Verify matched login, logout and accounting session records for one controlled test administrator. Capture request source IP and confirm the server recognizes it and returns valid responses. ExplanationCorrect Answer C:Verify matched login, logout and accounting session records for one controlled test administrator. This checks the affected traffic or control-plane behavior, not merely a generic up/down indicator. The underlying mechanism is: Authentication success does not automatically generate configured accounting records without an accounting method in scope. Other Answers A:Compare authenticated identity with EXEC privilege and authorization traces on test accounts. Authentication success does not automatically generate configured accounting records without an accounting method in scope. B:Show server accounting records containing administrator identities and executed commands. Authentication success does not automatically generate configured accounting records without an accounting method in scope. D:Capture request source IP and confirm the server recognizes it and returns valid responses. Authentication success does not automatically generate configured accounting records without an accounting method in scope.
Question 424 Remote AAA authentication works, but no administrator session start/stop records appear after a new accounting policy was deployed. Which lasting design or operational safeguard best prevents this particular issue from recurring? Define authentication, authorization and accounting as distinct requirements in device templates. Maintain offline-tested emergency credentials and a documented AAA outage procedure. Rotate AAA secrets as coordinated server/client changes with rollback and verification. Require accounting acceptance tests independently of authentication during access-control rollout. ExplanationCorrect Answer D:Require accounting acceptance tests independently of authentication during access-control rollout. This addresses the recurring cause: Authentication success does not automatically generate configured accounting records without an accounting method in scope. A targeted acceptance check is: Verify matched login, logout and accounting session records for one controlled test administrator. Other Answers A:Define authentication, authorization and accounting as distinct requirements in device templates. Authentication success does not automatically generate configured accounting records without an accounting method in scope. B:Maintain offline-tested emergency credentials and a documented AAA outage procedure. Authentication success does not automatically generate configured accounting records without an accounting method in scope. C:Rotate AAA secrets as coordinated server/client changes with rollback and verification. Authentication success does not automatically generate configured accounting records without an accounting method in scope.
Question 425 An extended IPv4 ACL permitting HTTPS to 203.0.113.20 is appended below a broader deny statement; the service remains unreachable. Which corrective action most directly resolves the documented failure without suppressing unrelated safeguards? Move the specific permit ahead of the matching deny while keeping the rest of the ACL's policy intact. 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. Verify feature support and compile an equivalent explicit supported ACE policy for the device release. ExplanationCorrect Answer A:Move the specific permit ahead of the matching deny while keeping the rest of the ACL's policy intact. Cisco ACL entries are evaluated in order and processing stops at the first match. Inspect hit counters for the deny and permit ACEs and test HTTPS plus denied non-HTTPS traffic. Other Answers B:Verify the actual traffic ingress path and apply the policy to the correct interface and direction. Cisco ACL entries are evaluated in order and processing stops at the first match. C:Add a narrowly scoped permit for the authorized DNS traffic before the implicit deny. Cisco ACL entries are evaluated in order and processing stops at the first match. D:Verify feature support and compile an equivalent explicit supported ACE policy for the device release. Cisco ACL entries are evaluated in order and processing stops at the first match.
Question 426 An extended IPv4 ACL permitting HTTPS to 203.0.113.20 is appended below a broader deny statement; the service remains unreachable. Which technical mechanism best explains the behavior observed in this scenario? uRPF depends on source-route lookup; losing a legitimate source route can make valid traffic fail reverse-path checks. 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. ACL object-group support and expansion depend on platform and software; unsupported constructs do not create intended matches. ExplanationCorrect Answer B:Cisco ACL entries are evaluated in order and processing stops at the first match. This explains why the initial condition produces the observed failure. The direct repair is: Move the specific permit ahead of the matching deny while keeping the rest of the ACL's policy intact. Validate through: Inspect hit counters for the deny and permit ACEs and test HTTPS plus denied non-HTTPS traffic. Other Answers A:URPF depends on source-route lookup; losing a legitimate source route can make valid traffic fail reverse-path checks. Cisco ACL entries are evaluated in order and processing stops at the first match. C: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. D:ACL object-group support and expansion depend on platform and software; unsupported constructs do not create intended matches. Cisco ACL entries are evaluated in order and processing stops at the first match.
Question 427 An extended IPv4 ACL permitting HTTPS to 203.0.113.20 is appended below a broader deny statement; the service remains unreachable. After applying the correction, which verification evidence most directly demonstrates that this issue is resolved? Verify the intended server application passes and an unauthorized source/port pair still fails. Check clock/timezone, active time range and backup traffic at the intended window. Inspect hit counters for the deny and permit ACEs and test HTTPS plus denied non-HTTPS traffic. Compare reverse-route lookup with ingress interface and confirm authorized asymmetric traffic passes after correction. ExplanationCorrect Answer C:Inspect hit counters for the deny and permit ACEs and test HTTPS plus denied non-HTTPS traffic. This checks the affected traffic or control-plane behavior, not merely a generic up/down indicator. The underlying mechanism is: Cisco ACL entries are evaluated in order and processing stops at the first match. Other Answers A:Verify the intended server application passes and an unauthorized source/port pair still fails. Cisco ACL entries are evaluated in order and processing stops at the first match. B:Check clock/timezone, active time range and backup traffic at the intended window. Cisco ACL entries are evaluated in order and processing stops at the first match. D:Compare reverse-route lookup with ingress interface and confirm authorized asymmetric traffic passes after correction. Cisco ACL entries are evaluated in order and processing stops at the first match.
Question 428 An extended IPv4 ACL permitting HTTPS to 203.0.113.20 is appended below a broader deny statement; the service remains unreachable. Which lasting design or operational safeguard best prevents this particular issue from recurring? Review IPv4 and IPv6 filters together in dual-stack hardening checks. Track required applications and implicit-deny cases in ACL policy matrices. Map interface/direction placement to forwarding paths during every ACL change. Use ordered exception reviews and negative tests before ACL deployment. ExplanationCorrect Answer D:Use ordered exception reviews and negative tests before ACL deployment. This addresses the recurring cause: Cisco ACL entries are evaluated in order and processing stops at the first match. A targeted acceptance check is: Inspect hit counters for the deny and permit ACEs and test HTTPS plus denied non-HTTPS traffic. Other Answers A:Review IPv4 and IPv6 filters together in dual-stack hardening checks. Cisco ACL entries are evaluated in order and processing stops at the first match. B:Track required applications and implicit-deny cases in ACL policy matrices. Cisco ACL entries are evaluated in order and processing stops at the first match. C:Map interface/direction placement to forwarding paths during every ACL change. Cisco ACL entries are evaluated in order and processing stops at the first match.
Question 429 A router's IPv4 ACL has permit statements for two user networks but silently drops DNS replies from a third required subnet. Which corrective action most directly resolves the documented failure without suppressing unrelated safeguards? Add a narrowly scoped permit for the authorized DNS traffic before the implicit deny. Move the specific permit ahead of the matching deny while keeping the rest of the ACL's policy intact. Repair authorized reverse-route visibility and then verify uRPF before disabling spoofing protections globally. Correct and synchronize device time and validate the referenced time-range configuration. ExplanationCorrect Answer A:Add a narrowly scoped permit for the authorized DNS traffic before the implicit deny. The end of an IPv4 ACL has an implicit deny for packets not matching any earlier permit. Inspect ACE hit counts and verify only the intended DNS exchange now passes. Other Answers B:Move the specific permit ahead of the matching deny while keeping the rest of the ACL's policy intact. The end of an IPv4 ACL has an implicit deny for packets not matching any earlier permit. C:Repair authorized reverse-route visibility and then verify uRPF before disabling spoofing protections globally. The end of an IPv4 ACL has an implicit deny for packets not matching any earlier permit. D:Correct and synchronize device time and validate the referenced time-range configuration. The end of an IPv4 ACL has an implicit deny for packets not matching any earlier permit.
Question 430 A router's IPv4 ACL has permit statements for two user networks but silently drops DNS replies from a third required subnet. Which technical mechanism best explains the behavior observed in this scenario? uRPF depends on source-route lookup; losing a legitimate source route can make valid traffic fail reverse-path checks. The end of an IPv4 ACL has an implicit deny for packets not matching any earlier permit. 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:The end of an IPv4 ACL has an implicit deny for packets not matching any earlier permit. This explains why the initial condition produces the observed failure. The direct repair is: Add a narrowly scoped permit for the authorized DNS traffic before the implicit deny. Validate through: Inspect ACE hit counts and verify only the intended DNS exchange now passes. Other Answers A:URPF depends on source-route lookup; losing a legitimate source route can make valid traffic fail reverse-path checks. The end of an IPv4 ACL has an implicit deny for packets not matching any earlier permit. C:IPv4 ACLs do not filter IPv6 packets; IPv6 traffic needs separate IPv6 policy and matching syntax. The end of an IPv4 ACL has an implicit deny for packets not matching any earlier permit. D:A standard IPv4 ACL matches source addressing only, while extended ACLs can match more packet fields. The end of an IPv4 ACL has an implicit deny for packets not matching any earlier permit.
