CCNA Day 3: VLANs, Trunking, and Layer 2 Security

Archive lab

Hands-on CCNA lab: build VLANs for Sales and Engineering, implement 802.1Q trunks with a hardened native VLAN, assign access ports, and apply sticky MAC port-security on access interfaces. The design uses a compact, realistic branch topology with a router-on-a-stick gateway, a distribution L2 switch, one access L2 switch, and two end hosts. Students deploy, verify, and troubleshoot VLAN reachability, trunk integrity, and port-security violations.

Learning objectives

• Configure and verify VLANs and switchport modes on Cisco switches
• Implement and test IEEE 802.1Q trunks with an explicit allowed VLAN list and a secured native VLAN
• Assign access ports to VLANs and connect endpoint devices
• Configure, verify, and troubleshoot basic sticky MAC port-security on access ports

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.