Certification793 problems· 22 reviewed

CCNA

793 incident response problems that help with CCNA prep.

All problems (793)

NETWORK-375AAA succeeds on the core path while device admin sourced from an out-of-band interface now hits a different policy realm than production traffic during a staged decommissionThe server is reachable, yet the management path is classified into the wrong authorization domain. The service still works through the primary path, but one dependency only fails when the old component is finally drained away.NetworkIntermediate15 minPro NETWORK-152An access switch voice VLAN is correct, but storm-control on multicast suppresses paging traffic only during announcementsThe network is healthy for normal calls, yet bursty multicast paging crosses a threshold the design did not anticipate.NetworkIntermediate15 minPro NETWORK-1292An HSRP pair passes failover tests but users still lose the first packets after recoveryA failover drill looks healthy on routers and users still report a short but repeatable outage window.NetworkIntermediate15 minPro NETWORK-1259An OSPF adjacency survives an MTU change until the process resets, making the network look healthy right up until the next control-plane restartThe neighbor remains Full after an interface MTU tweak, but the hidden mismatch only appears once the adjacency is renegotiated from scratch.NetworkIntermediate15 minPro NETWORK-1263DHCP helper traffic reaches the server but clients still never leaseNetwork incident scenario used for structured troubleshooting practice.NetworkIntermediate15 minPro NETWORK-1268DHCP helper traffic reaches the server but clients still never leaseA new VLAN is introduced and requests clearly hit the DHCP server, but clients remain without leases.NetworkIntermediate15 minPro NETWORK-1244DNS over TCP passes the manual test but users still failAn operator proves DNS works with one TCP command and later finds the production application still fails every ordinary lookup.NetworkIntermediate15 minPro NETWORK-1234DNS over TCP succeeds but ordinary lookups still failOperators validate a DNS query using TCP and wrongly conclude the general resolver path has recovered.NetworkIntermediate15 minPro NETWORK-1232A DHCP helper is reachable but one VLAN keeps getting addresses from the wrong subnetA user VLAN begins receiving the wrong address block even though the helper configuration still points at the same DHCP server.NetworkIntermediate16 minPro NETWORK-1242A DHCP helper reaches the server but clients still receive no leasesA new VLAN is added and helpers look correct, but every client request lands on a DHCP scope that is disabled or exhausted.NetworkIntermediate16 minPro NETWORK-1252A DHCP relay reaches the server but clients still get no leaseA new VLAN is introduced and requests hit the DHCP server, but the server still never hands out usable addresses to that segment.NetworkIntermediate16 minPro NETWORK-1247A DHCP relay reaches the server but clients still receive no useful leaseA new VLAN is introduced and requests hit the DHCP server, but every reply attempt still fails or returns unusable state.NetworkIntermediate16 minPro NETWORK-116A multi-auth 802.1X port authorizes the phone, but the PC loops through reauthentication when the data MAC ages outVoice stays online, yet desktop access flaps because the access policy handles multiple identities with different aging behavior.NetworkIntermediate16 minPro NETWORK-1288A NAT exemption rule looks correct but VPN traffic still translatesA site-to-site VPN works on the old firewall and breaks after migration even though the visible exemption rule was recreated.NetworkIntermediate16 minPro NETWORK-1279A policy-based route captures load-balancer health checks and sends replies out a different path, so the target never appears healthy even though the app works locallyThe server responds to the health endpoint, yet the reply exits a different interface because PBR catches that probe traffic and breaks symmetry.NetworkIntermediate16 minPro NETWORK-264A TACACS fallback local user exists while the AAA method list order never actually reaches it during timeout during a failover rehearsalThe backup plan is configured and the evaluation chain never invokes it. Normal traffic masked the issue until the standby or alternate path became active under rehearsal conditions.NetworkIntermediate16 minPro NETWORK-312AAA reachability survives while the method list order now prefers an unintended fallback before the authoritative server is tried during a failover rehearsalThe protocol path is there and the evaluation chain picks the wrong branch first. Normal traffic masked the issue until the standby or alternate path became active under rehearsal conditions.NetworkIntermediate16 minPro NETWORK-1229DHCP relays look correct but one subnet never gets leasesA newly carved subnet forwards DHCP requests successfully, but clients still fail to obtain usable leases.NetworkIntermediate16 minPro NETWORK-1213Gateway failover completes but one host still blackholes trafficA VIP or gateway failover succeeds for most clients but one host stays broken for several minutes.NetworkIntermediate16 minPro NETWORK-1209Host DNS tests pass but the daemon still uses the old addressA backend IP changes and dig looks right, but one long-running process still talks to the old endpoint.NetworkIntermediate16 minPro