Learn networking by building it

Hands-on CCNA labs and CCNP-level deep dives, all on real Cisco IOS XE with downloadable CML topologies. Zero fabricated output. Subscribe for new labs plus the free BGP, OSPF, and ASA field references.

Blog

View all

VLAN

VTP (VLAN Trunking Protocol): v1, v2, v3 and Why It's Dangerous

How VTP propagates VLANs across a domain, the three modes, the revision-number disaster, v1/v2/v3 differences, and why many engineers disable it.

Jun 17, 2026 5 min read

OSPF

OSPF Passive Interface: What It Does and Where to Use It

OSPF passive-interface stops Hellos and adjacencies on an interface but still advertises its subnet. Config, the default pattern, and the route-filter gotcha.

Jun 15, 2026 4 min read

Wireless

Catalyst 9800-CL Day 0 Configuration, Line by Line (9800 Series Part 2)

This is Part 2 of the PingLabz 9800 Wireless Labs series. In Part 1 we built the topology in Cisco

Jun 12, 2026 7 min read