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I have used virtualization in many different forms, OpenVZ, Xen, VMWare, for a number of years with great success. One thing I have been interested in doing is moving away from all applications that are not OpenSource. So finding a good solution for the Desktop virtualization has been a process. In that I am now running Debian 5 Lenny for the desktop workstation I thought I would try VirtualBox.

One of the newest features of Ubuntu 9.04 is the Postfix Mail Server/Dovecot enhancements to make it easier to set up a mail server. This article is a review of those improvements and a tutorial on how to fix several problems that were experienced.

One of the more controversial aspects of the Ubuntu 9.04 Jaunty Jackalope release is the use of the ext4 filesystem. Users have apparently lost important data already while testing Ubuntu on their desktop. This article provides some basic information about ext4 and then provides some test results on a Ubuntu 9.04 server.

CentOS 5.3 now comes with disk encryption. When you install the operating system you have the option to encrypt block devices, partitions that you create. Block device encryption requires a passphrase or key as authentication in order to access the data on that partition. The advantage of block encryption is that it will enforce the encryption even if the disk is removed from the operating system.

As an administrator the major interest that you will have with the web interface is the ability to recognize and respond to problems. The quickest access to all of the recognized problems is the “Service Problems” page. This page provides a summary of all problems related to services that Nagios detects.

Many websites offer feeds as a way to promote most recently added articles, stories or updates. Most of these are accessible through links titled “XML” “RSS” or “ATOM”. These different types of feeds all use the same fundamentals to bring you the latest from a specific website. By using feeds you can collect and read information on topics without ever visiting the website which the text belongs to.

Amavisd-new acts as a connecting point between Spamassassin, Clamav and Postfix. This is important to remember because much of the configuration that would seem to be done on Spamassasin directly, actually occurs in the amavisd-new configuration file.

There are a number of methods available to monitor Windows machines with Nagios. This tutorial will show you how to use NRPE and the NSClient++. This is probably the easiest method and provides the ability to monitor drive space, CPU, Memory, etc.

Webmin is a browser based program that you can use to manage a Linux server, from a remote location. It is an excellent tool for those who are making the transition from a GUI based system to the Linux command line. However, if you are going to use Webmin take a few security precautions first.

The Distribution List is a list of users that you can use to send mail to at one time. Instead of having to use CC: or BC: you can have a permanent list to send to. Zimbra offers a graphical interface to accomplish this task. This is a great way to send company mail to one user and it is distributed to the entire staff.

This is a five part series that shows you how to tune your web server for best performance. The series covers partition placement, CPU, I/O, Memory and Network.

There are 3 valuable tools that you can use from your desktop to review DNS settings; host, nslookup and dig. By using these tools effectively, you will be able to analyze your DNS settings to find problems. This tutorial will show you how to use each of these valuable tools.

Mutt is a text based email client that is both powerful and has a lot of features,some of which you will not find in other mail clients. One problem that you will see with many mail clients is that they do not work easily with IMAPS, or secure IMAP. Mutt integrates easily with IMAPS and is easy to set up.

One of the most popular programs for blogs and even content management is Wordpress. What makes Wordpress so popular is the ease of use, flexibility in set up and great support. Wordpress does an excellent job at providing documentation and options for everyday use.

Amavisd-new is used to allow ClamAv and Spamassassin to scan the incoming mail and then re-inject it into the queue again on a separate port. Since ClamAv and Amavisd-new are not in the repositories for CentOS you will need to add additional repositories to make it easy to install.

I had a client who needed an official SSL Certificate and had an account at godaddy.com. I have to confess, I really did not want anything to do with godaddy.com, based on their advertising methods and responses students and clients had made about them, nothing criminal just hard to get things done or changed. But…it made it much easier to use the features with godaddy.com than to go somewhere else for this client since they had a godaddy account. So I began the process of creating an official SSL certificate for them.

One of the most frustrating problems with setting up any mail server is the configuration required for anti-virus protection and Spam checking. Amavisd-new provides an excellent tool to help in setting that up. This is a step-by-step process in providing your mail server, the example is Ubuntu 8.10, with the ability to scan all incoming mail for viruses and Spam.

Using Truecrypt you can create an encrypted share for Samba. This is a scenario where you have Windows users who need to log into an encrypted directory that is mounted on a Linux Samba share. Of course you can also create encrypted volumes for Linux users.

There are network subnets that have been taken over by Spammers and run by bots. These networks are recorded and documented by Spamhaus and provide you a quick way to modify your firewall to eliminate these know blocks of Spam. You will need to have an iptables firewall and add this section to the firewall which will use the information found in the list to drop the subnets thus taking the load off your Postfix mail server.

Nagios is a free, open-source tool that can be used to monitor network components and services. When it detects a problem, it can send alert messages by either e-mail or pager. It can also be configured so that only designated personnel can view status information for particular services or equipment. This tutorial will show you how to install Nagios 3 on an Ubuntu 8.10 server.