Certification793 problems· 22 reviewed

CCNA

793 incident response problems that help with CCNA prep.

All problems (793)

NETWORK-1272HSRP failover works but failback hurts one applicationA failover event is handled correctly and the return to normal causes a second, more confusing outage window.NetworkIntermediate16 minPro NETWORK-1222HSRP state looks correct but one subnet still points at the old active routerA gateway transition works generally, but one user VLAN still reaches the old active router for several minutes.NetworkIntermediate16 minPro NETWORK-128IPv6 ND inspection keeps a stale binding after renumbering, and hosts with new addresses cannot pass traffic on the access edgeSecurity stays enabled, but address lifecycle assumptions lag behind the renumbered endpoint state.NetworkIntermediate16 minPro NETWORK-1184NAT forwarding stops after rebootA public NAT recipe worked during initial setup, but traffic stops on the next reboot because the sysctl was never made durable.NetworkIntermediate16 minPro NETWORK-1262A failover test appears healthy until traffic returns to the primary HSRP router and static ARP state on one path keeps forwarding from fully recoveringThe standby takeover works, yet failback breaks specific traffic because static neighbor state tied to the old active path does not refresh the way operators expect.NetworkIntermediate17 minPro NETWORK-1267A failover test appears healthy until traffic returns to the primary HSRP router and static ARP state on one path keeps forwarding from fully recoveringThe standby takeover works, yet failback breaks specific traffic because static neighbor state tied to the old active path does not refresh the way operators expect.NetworkIntermediate17 minPro NETWORK-252A QoS trust boundary shifts from phone to switchport while one access stack still rewrites DSCP at ingress during a failover rehearsalThe policy is consistent in design and one stack never received the new trust assumption. Normal traffic masked the issue until the standby or alternate path became active under rehearsal conditions.NetworkIntermediate17 minPro NETWORK-491AAA succeeds on the core path (Permission Denied)AAA succeeds on the core path (Permission Denied) focuses on Network Services And Operations and asks the reader to isolate Permission Denied in Cisco. 실무에서는 auth-and-session-failure 이슈를 볼 때 DNS, 라우팅, ACL/방화벽, 목적지 응답을 계층별로 잘라서 확인하면 장애 구간을 훨씬 빠르게 좁힐 수 있습니다.NetworkIntermediate17 minPro NETWORK-495AAA succeeds on the core path (Permission Denied)AAA succeeds on the core path (Permission Denied) focuses on Network Services And Operations and asks the reader to isolate Permission Denied in Cisco. 실무에서는 auth-and-session-failure 이슈를 볼 때 DNS, 라우팅, ACL/방화벽, 목적지 응답을 계층별로 잘라서 확인하면 장애 구간을 훨씬 빠르게 좁힐 수 있습니다.NetworkIntermediate17 minPro NETWORK-228An STP root move succeeds while BPDU guard from an access template errdisables the recovery uplink during a failover rehearsalThe topology change is valid and an inherited safeguard still treats it as hostile. Normal traffic masked the issue until the standby or alternate path became active under rehearsal conditions.NetworkIntermediate17 minPro NETWORK-1224DHCP relay looks right but one access stack still never gets leasesMost clients receive leases, but one switch stack does not after an access VLAN reshuffle.NetworkIntermediate17 minPro NETWORK-1219DNS over TCP works but UDP queries still failOperators validate a DNS query successfully over TCP and miss that ordinary client UDP traffic is still blocked.NetworkIntermediate17 minPro NETWORK-1185DNS resolution fails only inside containersAn operator validates name resolution on the host and assumes the container will behave the same way, but the runtime resolver path is different.NetworkIntermediate17 minPro NETWORK-1203Host DNS works but the proxy process keeps an old resolver view until it reloadsName resolution is fixed at the host level, yet one long-lived process still uses an older resolver state and continues sending traffic to the wrong backend.NetworkIntermediate17 minPro NETWORK-1212OSPF neighbors stay in Two-WayOperators see stable Two-Way neighbors and interpret it as a failure state.NetworkIntermediate17 minPro NETWORK-1181OSPF neighbors stay in two-way on shared segmentAn operator follows a Cisco Community thread after seeing two-way adjacency on a shared segment and escalates it as broken routing.NetworkIntermediate17 minPro NETWORK-551AAA succeeds on the core path (Permission Denied)AAA succeeds on the core path (Permission Denied) focuses on Network Services And Operations and asks the reader to isolate Permission Denied in Cisco. 실무에서는 auth-and-session-failure 이슈를 볼 때 DNS, 라우팅, ACL/방화벽, 목적지 응답을 계층별로 잘라서 확인하면 장애 구간을 훨씬 빠르게 좁힐 수 있습니다.NetworkIntermediate18 minPro NETWORK-555AAA succeeds on the core path (Permission Denied)AAA succeeds on the core path (Permission Denied) focuses on Network Services And Operations and asks the reader to isolate Permission Denied in Cisco. 실무에서는 auth-and-session-failure 이슈를 볼 때 DNS, 라우팅, ACL/방화벽, 목적지 응답을 계층별로 잘라서 확인하면 장애 구간을 훨씬 빠르게 좁힐 수 있습니다.NetworkIntermediate18 minPro NETWORK-1199ARP looks fine on one VLAN but the upstream gateway still misses repliesAn interface bounce after maintenance leaves one part of the forwarding path with stale or aged-out MAC state, so return traffic behaves inconsistently even though ARP looks normal.NetworkIntermediate18 minPro NETWORK-1214DHCP relay is configured but clients still never get leasesA switch shows the helper address on the intended SVI, but new clients still never receive leases after an access template change.NetworkIntermediate18 minPro