CCNA: VLAN DB & Trunk Allow-List Drift Recovery

Bundle lab · $29.99

Hands-on CCNA VLAN lab: build VLANs with names, assign access ports, harden and verify 802.1Q trunks, and troubleshoot a broken allow-list that prevents a VLAN from traversing the SW1–SW2 trunk. Includes router-on-a-stick gateways, management VLAN, and end-host validation.

Learning objectives

• Create VLANs and assign descriptive names in the VLAN database.
• Validate default VLAN 1 and the normal VLAN ID range on IOS switches.
• Assign switch access ports to user-defined VLANs.
• Configure and verify 802.1Q trunks with explicit allowed VLAN lists and a hardened native VLAN.
• Inspect VLAN database and confirm interface membership and tagging.
• Troubleshoot a connectivity outage caused by a missing allowed VLAN on a trunk.
• Demonstrate how adding/removing VLANs affects port membership and the vlan.dat database state.

Troubleshooting focus

• Verify every link's interface status and IP addressing (`show ip interface brief`) and correct any interface that is down or misaddressed.
• Confirm each device's running configuration matches the lab objective, and bring any interface, route, or service that is not in its expected state back to health.
• Trace end-to-end reachability with ping/traceroute and isolate the first hop where forwarding fails.