Securing Discovery on Edge Ports
Harden Cisco IOS edge interfaces by disabling CDP/LLDP toward untrusted endpoints while keeping discovery active on trusted infrastructure links. Routers share a management LAN with a server and form a direct router-to-router adjacency for CDP/LLDP. The learner enables discovery globally, selectively suppresses it on the client-facing edge, and verifies the outcome with show commands.
CDP Neighbor Discovery and Edge Suppression
Enable Cisco Discovery Protocol (CDP) on R1 to map directly-connected Cisco neighbors while suppressing CDP advertisements on the untrusted management-edge interface. Routers are directly cabled for true CDP adjacency and also share a common management LAN via SW1 alongside an Alpine MGMT host.
Discovery & Monitoring Troubleshooting Capstone
Troubleshoot a pre-broken monitoring deployment on a single shared management LAN. R1 is already configured for discovery and monitoring, but the NMS receives no syslog or SNMP traps from R1. Diagnose with show commands and correct the two seeded faults: wrong syslog target and missing SNMP trap generation. Deterministic, no-routing, single-subnet design for CML Free (5 nodes).
CCNA Lab 4: Native VLAN Mismatch Troubleshooting
Diagnose and remediate a trunk misconfiguration between an access switch and a distribution switch so that same-VLAN hosts across two access switches can communicate end-to-end. Use CDP and trunk verification commands to investigate the fault and restore proper trunk operation, without introducing any Layer-3 routing.