A Guide to IP Subnetting

Posted on Friday, Aug 17, 2018

The Basics of Binary

Counting In Binary

In order to understand IP subnetting it is important to first understand how to count in binary. As a first step, lets start with something familiar; counting in decimal.

Consider the progression of the following number sequence:

00
01
02
..
08
09
10
11
12
..
18
19
20

In decimal, there are 10 characters available for use: the numbers 0 through 9. Starting at zero, we count by incrementing the first column by one until we reach the final character of 9. At this point the first column resets to zero and the second column is incremented by one. We then iterate the characters in the first column until we again reach 9, at which point we repeat the process.

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An Introduction to IPSec VPN

Posted on Saturday, Sep 9, 2017

Introduction

IPSec is not a single protocol, but rather a suite of protocols designed to provide confidentiality, authentication, and integrity for a VPN. The following are used by IPSec to implement VPN:

  • Security Associations - a basic component of IPSec and contains information about the security parameters negotiated between peers.
  • Internet Key Exchange (IKE) - a control-plane protocol for management of the VPN tunnel.
  • Diffie-Hellman (DH) - the public key exchange algorithm used by IKE to create a secure channel for the control-plane.
  • Security Protocols - determine how data-plan traffic is carried through the VPN tunnel.

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vCenter REST API and the Content Library

Posted on Thursday, Apr 6, 2017

Overview

In this post I will demonstrate the use of the REST API to place an ISO image within the content library of vCenter, creating a new VM, and finally booting that VM from the ISO image.

I built these examples by following the documentation which is part of the REST SDK.

Getting Started

The examples assume the availability of a bash shell and curl, however, the tools themselves are not as important as the actual process.

Set Environment Variables

Store the base URL of the vcenter host. Example:

VCENTER=https://vc1

Generate a unique client token for use later on.

CLIENT_TOKEN=$(uuidgen)

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