Certification793 problems· 22 reviewed

CCNA

793 incident response problems that help with CCNA prep.

All problems (793)

NETWORK-103Root guard blocks the intended new spanning-tree root after maintenance and access switches stay pinned to the old pathThe maintenance plan is correct, yet the protection feature prevents the desired root election because the uplink role changed during rewiring.NetworkIntermediate16 minFree NETWORK-098Stack member replacement keeps the config but loses the DHCP snooping binding table after reloadUser traffic recovers briefly, then fails after reload because the new member does not retain the dynamic trust state the design relied on.NetworkIntermediate16 minFree NETWORK-070DHCP snooping uplink trust is missing after a switch replacement and clients lose gateway accessAccess ports still look normal, but ARP and DHCP behavior collapses because the new switch never restored the trusted uplink role toward the real infrastructure path.NetworkIntermediate18 minFree NETWORK-065Root guard errdisables the uplink after temporary loop prevention during maintenanceThe spanning-tree design is mostly correct, but a maintenance path unexpectedly presents a superior BPDU and the protected uplink shuts itself down.NetworkIntermediate19 minFree NETWORK-051OSPF passive-interface default suppresses the new transit VLAN neighborThe router has the right addressing and can ping the far side, but adjacency never forms because the new transit interface still inherits passive mode.NetworkIntermediate20 minFree NETWORK-042HSRP split behavior appears after trunk allowed list drops the failover VLANGateway redundancy works on most VLANs, but one subnet loses predictable failover because the standby control traffic no longer crosses the trunk everywhere it should.NetworkIntermediate22 minFree NETWORK-061DHCP relay helper is missing on the new SVI and only remote VLAN clients lose leasesLocal hosts work normally, but one moved VLAN never gets addresses because the relay path was not recreated on the replacement interface.NetworkBeginner15 minFree NETWORK-021Proxy forwards HTTPS as HTTP after port-based rule rewriteProxy forwards HTTPS as HTTP (Timeouts and Latency) is a hands-on troubleshooting drill. Traffic reaches the proxy, but a port rewrite changes the scheme assumption and breaks the application redirect flow. NGINX Firewall and Proxy Paths needs to be checked by narrowing scope,...NetworkBeginner15 minFree NETWORK-038Spanning tree root shifts after switch replacement resets bridge priorityA replacement access switch joins successfully, but traffic starts taking the wrong path because the expected root priority was never re-applied.NetworkBeginner16 minFree NETWORK-074DHCP Option 82 insertion changes and the server policy rejects every client from one access blockClient broadcasts arrive correctly, but the server stops leasing because relay metadata changed after an access switch template rollout.NetworkIntermediate17 minFree NETWORK-055DHCP relay helper is configured but the reply is blocked on the return ACLThe client broadcast is forwarded correctly, yet lease assignment still fails because the routed reply path is filtered differently on the way back.NetworkBeginner17 minFree NETWORK-034DHCP snooping blocks voice VLAN leases on a new access stackClients on the data VLAN receive addresses correctly, but phones on the voice VLAN fail because the uplink trust boundary or helper path was not mirrored.NetworkBeginner17 minFree NETWORK-010A missing WebSocket upgrade header drops real-time connectionsCovers a reverse-proxy misconfiguration where plain HTTP works but only WebSocket fails.NetworkIntermediate18 minFree NETWORK-007A missing ip_forward setting blocks NAT egress after a rebootCovers a kernel network setting problem that a temporary fix resolves but that breaks again after a reboot.NetworkIntermediate22 minFree NETWORK-1627A route-map change is correct and one neighbor still learns old communitiesOne neighbor still learns old communities after a route-map change.NetworkBeginner8 minFree NETWORK-1659A route-map change is correct and one neighbor still learns old communitiesOne neighbor still learns old communities after a route-map change.NetworkBeginner8 minFree NETWORK-1669A route-map change is correct and one neighbor still learns old communitiesOne neighbor still learns old communities after a route-map change.NetworkBeginner8 minFree NETWORK-1675A route-map change is correct and one neighbor still learns old communitiesA BGP neighbor still learns old communities after the route-map was updated.NetworkBeginner8 minFree NETWORK-1686A route-map change is correct and one neighbor still learns old communitiesA neighbor still learns old communities after the route-map was updated.NetworkBeginner8 minFree NETWORK-1696A route-map change is correct and one neighbor still learns old communitiesA neighbor still learns old communities after a route-map update.NetworkBeginner8 minFree