Rasila Garage

“The average spam messages per day is 18.5 and the average time spent per day deleting them is 2.8 minutes. The loss in productivity is equivalent to $21.6 billion per year at average U.S. wages.”

- Jesdanun, A. (2005), “Deleting spam costs billions, study finds”, The Associated Press Newswires (online)

Let’s say there are ten people working in your office and monthly cost per person is 4500€ (25,50€ per hour). By eliminating spam you could save 9:48 hours or 249,90€ per month totaling 2998,80€ per year the study says. Ok, I know I’m quantifying the unquantifiable, but the amount is anyway far greater than zero.

In my opinion the problem that is not solved yet is the deployment. I think every tech savvy person filters their spam already. But how about the rest of the people. Sure, you can use time and install a spam filter to each client, you can also install a spam filter to mail server and get more results.

If you wish to install spam filter to every client computer it will take lot of time and possibly people can mess up their installations. Updating lots of PCs does not sound like a good idea either.

Installing spam filter to a mail server sounds like a better idea but it might be that you cannot go to the mail server. Another problem would be that having a universal spam filter that works with any mail server is not reality.

But what about I you could just use hardware based solution that works out-of-the-box with any kind of setup. Wouldn’t that be cool? Perhaps the easiest way to eliminate spam in any POP3, IMAP & SMTP scenario would be to set up a network attached spam filter. This way would be 100% transparent to clients and completely platform independent. In SMTP scenario (You are not using mail server of your service provider, instead you have your own mail server) you can directly block spam before it goes to your mail server. You can also set up a simple shell script to automatically log in to your mail accounts and sweep the spam with Spamassassin. This would also be useful if you use a mobile device e.g. an iPhone to read your mail.

Untangle has made a great job by putting it all together and by offering the whole thing as an ISO-image. Their software is open source, licensed under GPLv2. All you are going to need is a extra computer with two network controllers.

To get started you should have following items:

• Untangle ISO image, and empty cd-r, obviously
• Extra computer with two nics, see hardware requirements

During the installation you might also need:

• a monitor
• an external CD drive

So, let’s get started with it.

I didn’t have extra computer for this so I ordered one. Here is my hardware configuration:

• Kingston Valueram 2GB 23,90€
• Intel Dual Core E5200 86,90€
• D-Link DGE-528T 14,70€
• Shuttle K45 barebone 111,90€
• 500GB HDD 56,90€
• Total 301,80€ with shipping.

This setup would be enough for pretty large network (maybe 200 clients). Hardware is not the case here, almost any x86 hardware should be just fine.

Unboxing and putting hardware together

Putting the hardware is an easy thing to do and even if you have not done it before I’m sure it won’t be a big problem. To me it took something like 15 minutes.

Since I think most of the readers might end up with a different hardware setup I won’t go thru putting the hardware together part any further. If you find any problems with the hardware, post a comment.

The installation process screenshots

Installing Untangle is quite straightforward process. My hardware setup did not have a CD-drive, keyboard, mouse or a monitor so I borrowed those from another computer. The mouse is essential! You cannot install Untangle without a mouse if you want to use the installer.

I think installation took something like half an hour for me, I didn’t time it. The installation wizard was easy to use and I sure most of the potential users with limited experience are fine with it.

My only complain would be the fact that in some step I needed a mouse to continue. I not sure if it was before or after the boot. Maybe text based installation option and SSH stating as a default would be a good idea for the future.

So as said, even thru Untangle pretty much works out of the box you should do some work more before you can remotely administer it.

Next couple of screens will guide you thru making basic settings and enabling the SSH server.

Configuration screenshots

Configuring Untangle is done with another wizard and it includes following steps:

- Agree with license, select password

- Select which network interface to use as external and which as internal

- Select router mode with NAT or transparent mode

Remote admin functionality is not on by default due the security reasons so in most cases you would like to put that on.

Putting SSH on is also a good idea and don’t forget to get SSH to the default runlevel. This is done by saying following to the terminal as a root:

/etc/init.d/ssh start
update-rc.d ssh defaults


Now that Untangle is installed and configured I would like to write few words about its capabilities.

Using Untangle

The beauty of Untangle is in its transparency. If you have only one computer I cannot see why you would like to install hardware based spam filter. But for network from couple to hundreds of clients PCs it is just great! After you get it up and running all the clients get the benefit of being spam free with no software installations and no new skills to learn. Sure this depends little bit of your configuration. It is going to be 100% transparent only if you will install it in front of the mail server you are using.

If you have a mail server outside of your network. You can use a small script called IMAP Spam Begone to sweep the spam on e.g. hourly basis. Installation is bit more difficult, I might write about it later on because it is generally useful.

The admin utility

Finally couple word about the admin utility. Untangle admin utility’s user interface looks like a server rack. Each component appears as a rack-mounted utility. I did not like the look of the UI for at first but it was simple to use.

Untangle’s spam filter is Spamassassin. The other components you can get to your rack are:

• Web Filter
• Spyware Blocker
• Protocol Control
• Virus Blocker
• Phish Blocker
• IPS
• Attack Blocker
• Firewall
• OpenVPN
• Reports Routing
• QoS

UPDATE: Statistics after about six weeks
It appears to be that after six weeks 121480 spam messages have been blocked and 1051 non-spam messages passed. Users are saying that they are virtually getting no spam at all. So I am pretty happy with it.

Tags: linux, Open Source, spam

This entry was posted on Monday, January 26th, 2009 at 5:12 pm and is filed under Business, Open Source. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.