Some engineers solving the original challenges Johannes posted complained that they were too easy, so he created another scenario: find out what’s wrong in an IPsec setup using just the captured traffic. Good luck!

Got this comment on one of my blog posts:

When looking at some of the CLIs just front-ending RESTAPIs, I wonder if "survival" of CLI isn't just in the eyes of the beholder.

It made me really sad because I wrote about this exact topic several times… obviously in vain. Or as one of my network automation friends said when I asked him to look at the draft of this blog post:

Omer asked a pretty common question about BFD on one of my blog posts (slightly reworded):

Would you still use BFD even if you have a direct router-to-router physical link without L2 transport in the middle to detect if there is some kind of software failure on the other side?

Sander Steffann quickly replied:

Validating the expected network behavior is (according to the intent-driven pundits) a fundamental difference that makes intent-driven products more than glorified orchestration systems.

Guess what: smart people knew that for ages and validated their deployments even when using simple tools like Ansible playbooks.

Dinesh Dutt explained how he validates data center fabric deployment during the Network Automation Use Cases webinar; I’m doing something similar in my OSPF deployment playbooks (described in detail in Ansible online course).

One of my readers sent me an interesting DMVPN routing question. He has a design with a single DMVPN tunnel with two hubs (a primary and a backup hub), running BGP between hubs and spokes and IBGP session between hubs over a dedicated inter-hub link (he doesn’t want the hub-to-hub traffic to go over DMVPN).

Here's (approximately) what he's trying to do:

David Gee (whom I finally met in person during recent ipSpace.net Summit) published a fantastic series of articles on what someone bringing together networking, development and automation should know and do.

In every SDDC workshop I tried to persuade the audience that the virtual appliances (particularly per-application instances of virtual appliances) are the way to go. I usually got the questions along the lines of “who will manage and audit all these instances?” but once someone asked “and how will we upgrade them?”

Short answer: you won’t.

I listened to Ethan Banks’ presentation on lessons learned running active-active data centers years ago at Interop, and liked it so much that I asked him to talk about the same topic during the Building Next-Generation Data Center course.

Not surprisingly, Ethan did a stellar job, and when I heard he was working on QoS part of an upcoming book asked him whether he’d be willing to do a webinar on QoS.

Some of the things Ethan Banks writes are epic. The latest one I stumbled upon: Things Network Engineers Hate. I particularly loved the rant against long-distance vMotion (no surprise there ;).

One of the design scenarios we covered in Leaf-and-Spine Fabric Architectures webinar is a pure layer-3 data center, and in the “how do I do this” part of that section Dinesh Dutt talked about the details you need to know to get this idea implemented on Cumulus Linux.

We covered a half-dozen design scenarios in that webinar; for an even wider picture check out the new Designing and Building Data Center Fabrics online course.