Leveraging Citrix XenServer Tools

Ideally, you should use the “Quick Instances” and other VM templates provided by our Xen Orchestra Dashboard when creating virtual servers for your project. These have been optimised with tools and drivers designed to get the best performance from your virtual machine, and to access advanced features such as safe shutdown in the event of power outage. But what if your VM was built from scratch, can you still access these tools?

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Use Certbot Standalone Mode to Retrieve Let’s Encrypt SSL Certificates

Watch out! This tutorial is over 1 year old. Please keep this in mind as some code snippets provided may no longer work or need modification to work on current systems.

Let’s Encrypt is a service offering free SSL certificates through an automated API. The most popular Let’s Encrypt client is EFF‘s Certbot.

Certbot offers a variety of ways to validate your domain, fetch certificates, and automatically configure Apache and Nginx. In this tutorial, we’ll discuss Certbot’s standalone mode and how to use it to secure other types of services, such as a mail server or a message broker like RabbitMQ.

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Using Xen Orchestra to create Virtual Machines

Watch out! This tutorial is over 1 year old. Please keep this in mind as some code snippets provided may no longer work or need modification to work on current systems.

Using VirtualBox, HyperV or similar in the labs is a great way to fire up Virtual Machines. However, this method pretty much ties you to that lab machine, unless you are willing to do a (pretty big) export/import of your VM on a regular basis… not very realistic. What if you could access your VMs from anywhere in the college… or even outside… using just a browser? Well now you can!

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Create a virtual encrypted disk within a file and mount it as a real disk

Watch out! This tutorial is over 1 year old. Please keep this in mind as some code snippets provided may no longer work or need modification to work on current systems.

VeraCrypt is a free open source disk encryption software for Windows, Mac OSX and Linux based on (the now defunct) TrueCrypt 7.1a. Features include:

  • Creates a virtual encrypted disk within a file and mounts it as a real disk.
  • Encrypts an entire partition or storage device such as USB flash drive or hard drive.
  • Encrypts a partition or drive where Windows is installed (pre-boot authentication).
  • Encryption is automatic, real-time(on-the-fly) and transparent.
  • Parallelization and pipelining allow data to be read and written as fast as if the drive was not encrypted.
  • Encryption can be hardware-accelerated on modern processors.
  • Provides plausible deniability, in case an adversary forces you to reveal the password: Hidden volume (steganography) and hidden operating system.

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How To Create a SSL Certificate for Apache

Watch out! This tutorial is over 2 years old. Please keep this in mind as some code snippets provided may no longer work or need modification to work on current systems.

SSL is based on the mathematical intractability of resolving a large integer into its also-large prime factors. Using this, we can encrypt information using what’s called a “private-public key pair”. Certificate authorities can issue SSL certificates that verify the authenticity of such a secured connection, and on the same note, a self-signed certificate can be produced without third-party support. By the end of the tutorial, you will have a web server accessible via HTTPS using a self-signed certificate.

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Understanding Binary

Watch out! This tutorial is over 2 years old. Please keep this in mind as some code snippets provided may no longer work or need modification to work on current systems.

The basic building block in all computers is the binary number system.

This system is chosen since it consists of 1s and 0s only. Since computers contain millions and millions of tiny ‘switches’, which must be in the ON or OFF position, this lends itself logically to the binary system. A switch in the ON position can be represented by 1; a switch in the OFF position can be represented by 0.

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