Astro Shapes Information Technology Blog - OpenSource

Replicating Package Lists in Ubuntu 7.10 - Gutsy

nospam@example.com (Craig Deering) — Mon, 04 Feb 2008 09:59:48 -0500

If you are attempting to build multiple Ubuntu server installations, here is some information you will find helpful in making each server have the same software packages. This is a quick way to bring up more than one server with identical package lists utilizing the dpkg technology.

First, build your first server exactly the way you want it. Once you are happy with the package list, get a command line and do:

# dpkg --get-selections > dpkg.list

You need to copy this file over to another server that you want to make the package base the same. Once there, you should make certain your package sources are up to date:

# apt-get update

Now, set the dpkg list to be the same as the other server:

# dpkg --set-selections < /tmp/dpkg.list

The package list is now the same, so have the system add/remove/update the packages to match:

# apt-get -u dselect-upgrade

That's all there is to it! You now have two servers with identical package lists!

Craig Deering
Network Engineer
Astro Shapes, Inc. - Aluminum Extrusions
Website - http://www.astroshapes.com

SpamAssassin, sa-learn and Thunderbird

nospam@example.com (Craig Deering) — Wed, 23 Jan 2008 10:14:45 -0500

Every once in a while, I find the need to do some manual training of my SpamAssassin Bayes database using sa-learn. I use Thunderbird as my mail client and there was no easy way to get the messages in an mbox format to perform the training.

What I had been doing was opening Evolution when I needed to do this, highlighting the messages, right clicking and selecting "Save As". This would save it out as an mbox type file.

This process was always a hassle for me. If I moved to a new laptop, I had to set up Evolution again.

The guys over on the SpamAssassin users list pointed something out. If Thunderbird is set up correctly, each folder is stored in the mbox format!! I don't need Evolution any more!!

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Migrating from Gentoo to Ubuntu Server

nospam@example.com (Craig Deering) — Wed, 16 Jan 2008 16:07:29 -0500

I have been a devout Gentoo fan for the last two or three years. I have used it personally on my laptop as well as on nearly every server I manage. While I loved the ability to tweak every aspect of the software I was using, I dreaded the unexpected reinstall because a laptop hard drive went bad. It could literally take three days to bring my laptop back to the way I wanted it. I recently gave Ubuntu a shot and was really impressed. Coming from an RPM based backend in the beginning, I really took to the way Ubuntu's Synaptic package management system worked. I also never liked the way Fedora required half a dozen CD's or a DVD to perform the install so I gave Ubuntu a try on the recommendation of a colleague.

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Port Bonding with Linux - Ubuntu Server

nospam@example.com (Craig Deering) — Tue, 15 Jan 2008 14:17:21 -0500

Many new servers come with multiple Network Interface Cards (NIC). Linux gives you the ability to "bond" those ports together to create a single usable interface. This gives you the advantage of fault tolerance and load balancing the NICs together. There are many different bonding types, but I will focus on the newer of them call balance-alb (Adaptive Load Balancing). It is great because it requires no special switch configuration and load balances both outgoing and incoming packets by influencing the switches by altering outbound ARP packets.

This procedure is using Ubuntu Server 7.10 (Gutsy). I was interested in making two separate bonds out of four interfaces, one for the corporate network and the other to connect the server to a SAN. The configuration for other types of Linux are similar in concept but usually have different configuration files.

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Remote Management Card with Ubuntu Server

nospam@example.com (Craig Deering) — Mon, 14 Jan 2008 21:56:51 -0500

I've wrestled with getting a remote management card working 100% with Linux and decided to document the process in case someone else was trying to do the same thing. I did this on a Tyan Barebones GT24 B2891, a Tyan System Management Daughter Card M3291 and Ubuntu Server 7.10 (Gutsy). The specs of the server probably have no bearing to making this work. This should also adapt with many other set ups.

The goal of this project was to build a server where I had remote capabilities such as cycling power, monitoring vital statistics like CPU temp and fan speed, and gain console control during the boot process so I could make changes to the BIOS settings remotely. You also gain the advantage that if network services like telnet or SSH become unavailable, you can likely still use the remote console.

Some manufacturers include this capability into their equipment. Many of them call it "Lights Out" administration. The Tyan equipment I purchased needed a card added and set up. If anyone is interested in the hardware installation including the firmware updates, let me know and I'll write it up. This document is strictly dealing with the Linux setup.

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Hardware, Software or Fake RAID?

nospam@example.com (Craig Deering) — Sat, 05 Jan 2008 15:30:15 -0500

Over the last few years, I've resorted to building my own servers out of barebones equipment for a varying number of reasons (beyond the scope of this article). One of my biggest hurdles has been deciding the storage architecture I want to use.

With the advent of the SAN, the hard drive requirements of the server have drastically changed. If I have a high powered SAN with dozens of high RPM SCSI drives that handle the bulk of the file storage, does the server need SCSI drives itself? If the server is running mostly from RAM and using the local drives for nothing other than log files and binaries, then the answer is no.

So the next question becomes, how do I keep the OS fault tolerant of a hard drive failure? I could go expensive and use a hardware RAID in the form of a card... I could go with a software RAID provided by my Linux kernel... Or I can use the BIOS RAID supplied by my BIOS...

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Microsoft Outlook and Winmail.dat Files

nospam@example.com (Craig Deering) — Fri, 30 Nov 2007 14:51:53 -0500

As an opensource shop, one of the strangest problems we had to face with email is the way Microsoft Outlook/Outlook Express handles email attachments. They decided to encode the attachments into a single attachment and name it winmail.dat. Third party applications don't seem to want to open it. So how do you get around it?

Here's how we did it!! We process our email in-house and MIMEdefang is one of the packages we use. If you've never heard of it, MIMEDefang lets you inspect, modify, bounce and reject email before it is passed on to the next mail server. You can strip out potentially harmful attachments like .exe, .scr, .bat, etc... It also lets you check for viruses, Spam and other unwanted content. If you can dream it up, you can get MIMEDefang to do it.

When an attachment comes through and it is of the winmail.dat variety, simply let MIMEDefang run a procedure against it to extract the real attachments and discard the winmail.dat part.

See the extended article for detailed code.

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