Preface

Some of my readers today will be aware of a beautiful operating system that goes by the name of Linux. For those who are not already familiar, here is a brief introduction: Linux is a free open-source alternative to Windows and Macintosh. Based off of Unix, Linus Torvalds laid the framework for the kernel many years ago and then made the source code open to all. He still works on the kernel today, but he’s not alone; millions of programmers around the world work to improve Linux with their free time. They’ve worked hard to bring Linux to maturity, and as of the past couple years, it has reached a mature stage where the average computer user is more than capable of using it. In other words, you no longer need to know how a computer works or how to program in order for Linux to be useful to you.

So why am I bringing up this topic? Quite frankly, there aren’t enough Linux users accessing TechwareLabs, and I believe this needs to change.

Whether it’s because you’ve never heard of Linux, have an interest, or tried it years ago when it was still young and was disappointed, one thing is certain: you’re missing out. I’ll be elaborating further into Linux in future articles, but for now, here is a nice introduction.

What do you mean by open-source?

The source code is freely available on the internet per the GPL license. You are more than welcome to view the code, edit it, and republish a new product (assuming you know a thing or two about programming). The only catch is that you have to release your product under the very same GPL license.

This approach to software truly throws the concept of “proprietary” out the window, and is no doubt confusing to anybody who is business-minded. It’s a foreign concept for many as to why one would develop a product and not claim intellectual property rights. The Linux community, in general (though there are exceptions), does not seek to gain profit. Rather, they put their time into Linux for pride and the occasional “thank you.”

There are companies that sell Linux, though.

This is partially true. They’re still licensed under the GPL, which means they are required to release the source code to the general public. What companies such as Red Hat and Novell are doing is not selling the operating system, but rather they are selling support, primarily for servers. Even so, you can use their products for free. Red Hat Enterprise Linux has fees attached to it, but Red Hat sponsors an open-source community around Fedora, which is the free alternative, developed by programmers in their spare time. Similarly for Novell SUSE Linux Enterprise, there is a free alternative in openSUSE.

Windows works fine. Why should I use something else?

Here, we get to the heart of the matter. Why switch, you ask? What’s the point? Simply put, Linux is faster, more stable and above all, easier to use. The speed is due to higher efficiency in storing/retrieving information. The issue of stability isn’t even questioned by [knowledgeable] die-hard Windows fans. Ultimately, the most controversial claim I’ve made is that it’s easier to use.

This is where the argument rages on within the desktop market. There are many long-time Windows users who try Linux, and are scared off, upon which they claim that Linux is hard to use. The fact is, Linux is different, but I would argue that this is a good thing. There is definitely a learning curve, as there always is when you try something new, but the more you just play around with Linux, the more you’ll find it is simply better.

How is it better? What makes it easier?

Everything is better organized. For starters, you know that little program on Windows, Add/Remove Programs? Raise your hand if you’ve ever actually “added” a program using it.

I see a few hands from people who have via a NT system or something similar, but other than that, it is unlikely you’ve used Add/Remove for anything other than “remove” (though Vista does allow for the user to download programs directly from Microsoft, a feature suspiciously appearing long after Linux started doing the exact same thing). In Linux, this little program is called the “package manager”, and this is where you both add AND remove your programs. Everything that’s currently installed, as well as everything you’re able to install from the supplied servers appears in an easy-to-use catalog. For the most part, everything you need is right there in one place. Want to install an office suite? How about an IM program? Or how about a game? Just go to the respective section and choose the program you want. Check the boxes for everything you want to change (install/uninstall) and push the appropriate button to update your system (specifics will differ depending on the package manager used by the distribution).

Open ~/.profile file and the following line:

export KWIN_NVIDIA_HACK=1

For more on this check COMPOSITE_HOWTO. Now see the difference.

Tip: In loads cases, overall smoothness may be increased by turning off direct rendering in advanced options in the Desktop Effects configuration module (Alt+F3->Configure Window Behavior).

No optimastion or tweaks for ATI video cards that I have noticed so far. If you know, let us know.

Privoxy

Privoxy is a standalone application full of impressive features. It’s a breeze to install. Its default settings are ideal for most users. Fedora and Ubuntu users can respectively install it with the commands yum install privoxy and sudo apt-get install privoxy, or you can grab the source tarball and install it with the commands ./configure, make, make install. Once installed, Privoxy will bind to localhost (127.0.0.1) at port 8118. You can choose a different port and network interface during the manual installation, or specify it under section 4.1 of the /etc/privoxy/config file.

You need to inform your browser about Privoxy before you begin using it. In the Firefox preferences dialog box, click Advanced and then click the Network tab, and click the Settings button under Connection. Choose Manual proxy configuration and fill in 127.0.0.1 and port 8118 for HTTP proxy. Make sure localhost or 127.0.0.1 are not listed in the “No proxy for” field. You can now access the Privoxy browser interface at http://p.p/

Privoxy has two sets of configuration files. You can filter HTML, CSS, JavaScript, and other content using the filter files. The default filter rules are defined in the /etc/privoxy/default.filter file. The other set of files, which are called action files, define what action Privoxy should take for each Web site it encounters. The rules for cookies, ads, and other objects are defined in action files. On a default installation, Privoxy disables banner ads based on size, all popup windows, and Google ads. The default action rules are contained in the /etc/privoxy/default.action file. All configuration files rely on regular expressions, so unless you are confident about what you are doing, do not edit the default.filter or the default.action files. Unfortunately you can’t edit the files through the browser interface.

Webcleaner

Webcleaner can do everything Privoxy can, and it also has an antivirus filter and can reduce images on a Web site to low-bandwidth JPEGs. Unlike Privoxy, the Webcleaner browser interface can be used to handle the configuration. However, Webcleaner makes users suffer through a demanding installation. It requires tools such as Python Image Libraries (PIL) and Clamav to be installed if you respectively wish to use the image compression and virus filter features. To apply content filtering to SSL-encrypted Web pages, you need to additionally install the Open-SSL and Python-openssl packages, in addition to Python 2.4 and Runit (a replacement for the init system), and although the software’s requirements don’t list it, I had to also install the python-devel package.

If you follow the installation instructions, you should be able to bring up the browser interface. Make sure your browser proxy settings point to 127.0.0.1 and port 8080 instead of the 8118 used for Privoxy. Open a terminal window, start Webcleaner with the command webcleaner, then point your browser to http://127.0.0.1:8080. You will see two passwords on your screen; edit the /usr/share/webcleaner/config/webcleaner.conf file and look for the adminpass="" line. Fill in the MD5 password generated by Webcleaner into this field. The other password you’ll use to log in to Webcleaner. Now you can restart Webcleaner. This time, visiting http://127.0.0.1:8080 will bring up a login screen.

I find the Webcleaner interface a little complicated. While it’s well-categorized and moving around is easy, when it comes to adding your own filter settings, Privoxy wins hands down. Like Privoxy, Webcleaner blocks ads and deanimates GIFs out of the box. But on a few sites, I found it had corrupted the text flow by removing the ads.

Dansguardian and Squid

A third alternative, and one of the most popular content filter setups, involves two applications. The actual filtering is performed by DansGuardian. It allows you to filter Web pages based on exact phrase matching, and also supports Platform for Internet Content Selection (PICS), which means you can filter pages with possible objectionable content. You can even configure DansGuardian to use third-party blacklists or use it to maintain one of your own.

Squid is a proxy server that supports HTTP and FTP, but it has limited support for other protocols, such as TLS and SSL. In this setup, Squid fetches Web pages and feeds them to DansGuardian. (You can configure DansGuardian to work with any proxy server.)

Once installed, Squid binds to port 3128 — but DansGuardian listens on port 8080. This means you need to use iptables to redirect all traffic to port 8080 as we’ve discussed in the past.

Final verdict

Both Webcleaner and DansGuardian are useful if you’re prone to virus attacks. Their only downside is that while Webcleaner has an uncomfortable configuration system, Dansguardian is not a standalone application. Privoxy, with its ease of use and impressive features, should suffice for any home user on most networks.

This how to uses Ubuntu 7.10 Server install. I am sure that this could be done with a much smaller install base, rather than server – I might have used the Alternative CD, or maybe even some other distribution like DSL, or Puppy Linux (if you needed GUI [graphical user interface] ). But for proof of concept this worked fine. I used an Old Dell GX100 Optiplex with 256 MB of RAM (I don’t think I need any more that 128 [maybe even 64MB], but this is what was in the box when I pulled it out of the pile). It has a small form factor, and runs pretty quiet. My steps are geared toward English & US, so you may want to change those if your using something else =).

Read more…

Install Debian. I used the basic barebones install option. I did
some things that were done because of preference, and not necessary. I
have marked them approriately. I encourage contributions from anyone
who would like to add or correct something in this HowTo to contact me
so I can fix it. I have installed this setup twice following these
instructions and used Avantfax 2.3.0. Thanks to all the resources who
helped me figure this out. Especially Razametal, who submitted a
fantastic Spanish language walkthrough on ecualug.org.

Read more…

There are already tons of written Snort rules, but there just might
be a time where you need to write one yourself. You can think of
writing Snort rules as writing a program. They can include variables,
keywords and functions. Why do we need to write rules? The reason is,
without rules Snort will never detect someone trying to hack your
machine. This HOWTO will give you confidence to write your own rules.

Read more…

It’s very simple to masquerade (internet connection sharing in
Windows language ) on Linux with a few lines of iptables and ip_forward
commands.

Read more…

This document describes how to set up Hyperic HQ on Fedora 8. The
resulting system provides an awesome, web-based “System
ManagementSoftware”. It’s the next stage of classical monitoring and
able to manage all kinds of operating systems, web servers, application
servers and database servers.

Read more…

DRBD is an abbreviation of Distributed Replicated Block Device.
DRBD is a block device which is designed to build high-availability
clusters. This is done by mirroring a whole block device via (a
dedicated) network. You could see it as a network RAID1.

Read more…