Cisco ASA packet-tracer Command: Complete Troubleshooting Guide
If you only learn one Cisco ASA troubleshooting command, make it packet-tracer. It simulates a single hypothetical packet through every
9 min read
Blog
members
OSPF Field Reference (9-Page Printable Cheat-Sheet)
OSPF has a lot of moving parts. The state machine. The LSA types. The area types and what each one
3 min read
members
BGP Field Reference (9-Page Printable Cheat-Sheet)
BGP has a lot of moving parts. The state machine. The 13-step path-selection algorithm. The dozen knobs that influence which
3 min read
GRE on Linux: ip tunnel add Commands and Examples
Configure GRE tunnels on Linux with ip tunnel add. Cisco-to-Linux interop, MTU, MSS clamping, IPsec, gretap (L2), and persistence with systemd-network
7 min read
GRE Tunnel Troubleshooting Guide
Step-by-step GRE tunnel troubleshooting on Cisco IOS XE. Five-minute triage, recursive routing, MTU drops, keepalive flap, debug commands, and EPC cap
8 min read
mGRE and DMVPN Introduction
Multipoint GRE, NHRP, and IPsec combined to form DMVPN. The three phases, hub and spoke config for Phase 3, verification commands, and design tradeoff
7 min read