CCIE-level material for engineers past the CCNP line. Articles tagged CCIE cover expert-track routing, overlays, security and automation, with full configs and real device output from CML.
ESP has no port numbers, so PAT kills raw IPsec: Phase 1 comes up, Phase 2 passes nothing. This article shows why, what NAT-T actually changes on the wire, and the failure and the fix in real CLI output from a live CML lab.
Configure GRE over IPsec on Cisco IOS XE with IKEv2 and IPsec profiles. Modern and legacy configs, MTU planning, OSPF over the tunnel, and gotchas.
What an SA is, why IKE runs in two phases, and which bytes of your packet actually get encrypted. Grounded in real packet captures on the transit link between two Cisco IOS XE edge routers in a CML lab.
Complete site-to-site IPsec VPN build with crypto maps on IOS XE: ISAKMP policy, keys, transform set, interesting traffic, and the crypto map itself, with every line of CLI output captured from live cat8000v routers in CML.
Model-driven telemetry replaces SNMP polling with continuous streaming from the device. This article covers the MDT subscription model on IOS XE, dial-in vs dial-out over gRPC, and the honest platform picture.
Go past one-line EEM applets: multi-event correlation, Tcl policies, and EEM as the trigger for on-box Python. Includes a real applet firing and capturing device state in a CML lab.
One interface configuration rendered as JSON, XML, and YAML from a single Python dictionary. See why RESTCONF, NETCONF, and Ansible each picked their format and how all three encode the same data model.
Stop hand-editing pasted router configs. This post builds the full templating pipeline: YAML variables, a Jinja2 template, rendered CLI, and a Netmiko push to a live router, all captured from a real CML lab.