Above is a Topology that demonstrates a few things right off the bat, A) it wants to establish an mGRE Tunnel to Branch2 from Branch1, b) To do this it needs to send an "NHRP Query" Packet to the NHRP Server HubRouter to get information on HOW to create a tunnel with Branch 2, c) … Continue reading DMVPN – NHRP Client / Server Protocol review, how dynamic tunnels are formed, the different NHRP Phases, and an Intro to DMVPN definitions!
This will be so basic that I am not sure exactly why I am posting, except for the sake of a refresher to this material, as the name implies instead of doing a "GRE to GRE" tunnel, we are creating Multi-GRE Tunnels with the help of NHRP (Name Hop Resolution Protocol), to allow spoke sites … Continue reading DMVPN – mGRE review of NHRP Servers and Client configurations (nothing labbed), and a glimpse out IPSec configuration at the very end!
I initially stuck my TSHOOT GRE Deep Dive into the CCIE DMVPN bucket, but there is no such thing as too much practice or repetition, so get ready for some more here 🙂 Back to the basics of GRE and why this ancient protocol has any relevance It routes almost ANY kind of traffic which … Continue reading DMVPN – Review of GRE Tunnel setup, do’s and dont’s for configuration, case uses for a GRE Tunnel, and more!
The graphic above shows a VPN Tunnels two modes (Transport and Tunnel), along with how their payloads differ when configured with AH (Authentication only) and ESP (Encryption) on the tunnel, and what protocols correlate with all of it. (After watching the content of the CCIE R/S VPN Technology course, this article more than sums up … Continue reading TSHOOT – GRE DEEP DIVE!!! MTU / Fragmentation / TCP-MSS / PMTUD / Recursive Routing / Interface States / must know information for exam day!