PortFast skips the 30-second spanning tree wait so a host gets an IP the moment it plugs in. This post covers where it belongs, where it can take down a network, and the two guard features that keep it safe.
The native VLAN is the one untagged VLAN on an 802.1Q trunk, and it can break a link through a mismatch or get hopped through double tagging. This post explains why it exists, both failure modes, and how to configure it safely.
CML 2.10 shows the Docker node definitions but no image definitions. Here is how to install the container images (net-tools, nginx, Snort, TACACS+, Splunk and more) from Cockpit.
Still worth it for most people, with one big caveat. The honest take on the 2026 to 2027 exam change, what the cert actually gets you, and the AI question.
Before LSA types make sense, you need what an LSA actually is: one record in the link-state database describing one piece of the network. This post covers the LSA as a building block and how it gets everywhere it needs to be.
Basic BGP peering takes half a dozen lines; what trips people up is eBGP vs iBGP behavior, getting routes into BGP, and the iBGP next-hop quirk that silently breaks reachability. A full IOS XE walkthrough.
Every Cisco AP mode explained: Local, FlexConnect, Monitor, Sniffer, Rogue Detector, SE-Connect, Bridge and Mesh. What each does and when to use it.
SR-MPLS keeps the MPLS data plane and drops LDP and RSVP-TE. Prefix-SIDs, adjacency-SIDs, source-routed label stacks, SR-MPLS vs SRv6, and why networks migrate.
How VTP propagates VLANs across a domain, the three modes, the revision-number disaster, v1/v2/v3 differences, and why many engineers disable 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.
The 5 things that must match for EIGRP routers to become neighbors: subnet, AS number, K-values, authentication, and process membership. Plus what does NOT need to match.
Per-VLAN Spanning Tree explained: PVST+ vs Rapid-PVST+, the sys-id-ext Bridge ID trick, per-VLAN root placement for uplink load balancing, and when to move to MSTP.