Author: David Varnum

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Securing Bitcoins with TREZOR

TREZOR is a hard wallet for securely storing crypto assets such as Bitcoin, Ethereum, and Litecoin. Protection mechanisms like a mnemonic recovery seed, PIN, and encryption passphrase safeguard your assets (private keys) by requiring your physical interaction in order to make transactions. (more…)

Leveraging SD-WAN for Mergers & Acquisitions

A colleague recently asked me if SD-WAN could be leveraged to expedite network integration as a result of a merger or acquisition. His thoughts were that this could potentially provide a means to securely integration networks in a short amount of time. At first I thought this made no sense — SD-WAN is not related to this challenge whatsoever. However, the idea stuck in my head like a bad catchy tune. I started thinking… maybe in certain circumstances this could work? This post is a collection of some ideas I’ve been brewing with respect to the secure and timely integration of disparate networks using over-the-counter SD-WAN. (more…)

Issue deploying CSR on ESXi vSphere 6.5

I recently ran into a slight bump when deploying the Cisco Cloud Services Router 1000v (CSR) on ESXi vSphere 6.5. The error message I received when trying to deploy the CSR OVA was:

VALUE_ILLEGAL: Value “VMXNET3 virtio” of ResourceSubType element not found in [E1000, VmxNet2, VmxNet3].

(more…)

OCSA Passed!

It’s official – I passed the ONF Certified SDN Associate exam. I’m OCSA #SDN10356!

If you’re interested in obtaining this certificate, I recommend you read through my short blog series covering the resources necessary on the blueprint. (more…)

ONF Certified SDN Associate (OCSA) – Part 5

The OCSA exam tests your understanding of components in an SDN framework, your ability to articulate the fundamental workings of networking and the OpenFlow protocol, as well as your knowledge of vendors, solutions and projects available in the SDN landscape. (more…)

ONF Certified SDN Associate (OCSA) – Part 4

ONF Certified SDN Associate (OCSA) – Part 3

ONF Certified SDN Associate (OCSA) – Part 2

ONF Certified SDN Associate (OCSA) – Part 1

The concept of SDN is constantly evolving. There are countless adaptations, projects, solutions, and products in this market, and we’ve just begun to see the impact. Developed network engineers will want to stay informed in this age of great change. This is why the Open Networking Foundation (ONF) put together a certification program for SDN. (more…)

Flowsim – A Web-based OpenFlow Learning Tool

Just discovered a tool developed by OpenFlow researchers and engineers called Flowsim. It’s been around for a couple of years, I’ve just never got around to using it. It’s a tool that helps you visually learn OpenFlow. It runs entirely in your browser, and all you need is a free account to get started.

You can configure OpenFlow switches and setup packets to be sent through the OpenFlow pipeline. If you’re curious about the underworkings of OpenFlow and don’t feel like setting up your own lab, definitely check it out. (more…)