3 hands-on PortFast scenarios you build in your own Cisco Modeling Labs instance and grade against the answer key. Focused PortFast configuration and troubleshooting practice for CCNA and CCNP.
Continue the STP series on a three-switch triangle with a real loop. SW1 is the deterministic root for VLAN 60, and access ports already use PortFast. In this lab you will harden the edge by enabling BPDU Guard on the two host-facing access ports on SW2 and SW3, while leaving the inter-switch trunks untouched. Verify with show commands that BPDU Guard is active only on the edge and that hosts still communicate normally.
Engineer which trunk forwards by tuning STP path cost in a 3-switch triangle. Force SW1 as the VLAN 30 root at a deterministic priority, enable Rapid-PVST+, harden edge ports with PortFast and BPDU Guard, and raise the STP cost on SW3’s direct uplink to SW1 so SW3 prefers the longer, indirect path via SW2. Verify the resulting root port, alternate (blocked) port, and host reachability across the chosen path.
Configure PortFast correctly on access ports in a triangle switch loop while maintaining normal STP protection on inter-switch trunks. Force SW1 as the root for VLAN 50 and verify that only edge ports are fast-tracked. Observe the difference in host convergence with and without PortFast.
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