This tutorial shows how you can use a free Class1 SSL Certificate from StartSSL to secure your ISPConfig 3 installation and get rid of self-signed certificate warnings. The guide covers using the SSL certificate for the ISPConfig web interface (both Apache2 and nginx), Postfix (for TLS connections), Courier and Dovecot (for POP3s and IMAPs), and PureFTPd (for TLS/FTPES connections). If you've installed monit and use HTTPS for its web interface, I will show you how to use the StartSSL certificate for it as well. This guide assumes you use Debian or Ubuntu; the principle is the same for other distributions supported by ISPConfig 3, but paths might differ.

http://www.howtoforge.com/securing-your-ispconfig-3-installation-with-a-free-class1-ssl-certificate-from-startssl

This document describes how to install a Postfix mail server that is based on virtual users and domains, i.e. users and domains that are in a MySQL database. I'll also demonstrate the installation and configuration of Courier, so that Courier can authenticate against the same MySQL database Postfix uses. The resulting Postfix server is capable of SMTP-AUTH and TLS and quota. Passwords are stored in encrypted form in the database. In addition to that, this tutorial covers the installation of Amavisd, SpamAssassin, ClamAV and SquirrelMail.

http://www.howtoforge.com/virtual-users-and-domains-with-postfix-courier-mysql-and-squirrelmail-centos-6.2-x86_64

Here is the guide on installing Firebird 2.5.1 from FreeBSD 9 Ports and creating your first test database; also we show you how to install Flamerobin GUI (administration tool) and the PHP driver for it. This was tested on fresh FreeBSD 9 on a kvm-linux virtual machine.

http://www.howtoforge.com/the-perfect-database-server-firebird-2.5.1-and-freebsd-9

This tutorial provides step-by-step instructions on how to install Xen (version 4.1.2) on a CentOS 6.2 (x86_64) system. Xen lets you create guest operating systems (*nix operating systems like Linux and FreeBSD), so called "virtual machines" or domUs, under a host operating system (dom0). Using Xen you can separate your applications into different virtual machines that are totally independent from each other, but still use the same hardware.

http://www.howtoforge.com/virtualization-with-xen-on-centos-6.2-x86_64-paravirtualization-and-hardware-virtualization

This tutorial shows how to convert an existing CentOS VM to a physical machine. This tutorial covers the cloning of the VM to an unpartitioned HDD and troubleshoot some of the possible errors that you may have booting the OS on your new hardware. To illustrate this procedure I will use VMware Workstation 7 as the handler to transfer the VM installation to a physical HDD.

http://www.howtoforge.com/converting-a-vmware-image-to-a-physical-machine

This article is about how to create a DVD image of your machine with the exact same software included on the disk. This can be done using a software called Relinux. Relinux is a fork of the recently discontinued Remastersys.

http://www.howtoforge.com/creating-your-own-distributable-ubuntu-dvd-relinux

Basic Linux system auditing is a bit tricky and data collected and information of that is out of place and readability is not that good. Recently this lead me to put together a Open Source code project and develop simple BASH scripts that do the job nicely. The code and tar ball can be downloaded from both google code or from SourceForge's website and the project website has links to documentation, help, installation and code.

http://www.howtoforge.com/simple-linux-auditing

Dualbooting means having installed two operating systems on one hard disk and being able to boot from any of them. This tutorial will explain how to install Linux Mint 12 alongside Windows 7 - the procedure however should be the same for all Ubuntu based distributions and only slightly different for every other.

http://www.howtoforge.com/dualbooting-windows-7-and-linux-mint-12

This document describes how to deploy AVG Antivirus for Linux/FreeBSD to a Postfix mail server. It is usable for AVG version 8.5, 10 and 2012. By using AVG Antivirus with your Postfix mail server, you can ensure virus-free inboxes.

http://www.howtoforge.com/avg-antivirus-for-linux-freebsd-plus-postfix-mail-server

This guide explains how you can run virtual machines with VirtualBox 4.1 on a headless Ubuntu 11.10 server. Normally you use the VirtualBox GUI to manage your virtual machines, but a server does not have a desktop environment. Fortunately, VirtualBox comes with a tool called VBoxHeadless that allows you to connect to the virtual machines over a remote desktop connection, so there's no need for the VirtualBox GUI.

http://www.howtoforge.com/vboxheadless-running-virtual-machines-with-virtualbox-4.1-on-a-headless-ubuntu-11.10-server