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How to install Ubuntu Linux on the decTOP SFF computer |
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I recently bought a decTOP small form factor (SFF) computer. My goal was to build a cheap, fanless, quiet, and low power consumption Linux server. For $99 plus the cheapest available shipping, $40, my machine arrived 11 days after I placed the order. This is a tiny computer, about the size of a Mac Mini. But, because it has no fan, it runs a bit quieter and, with the help of a 1-watt, 366 MHz CPU, consumes only 8 watts. For comparison, the G4 Mac Mini consumes about 20-30 watts, depending on load. The decTOP comes with 128 MB of RAM in its sole SO-DIMM slot and a 10 GB 3.5 inch hard drive. I understand that it's a simple matter to replace the drive and to upgrade the memory to a maximum of 512MB. It also comes with no operating system and the ability to boot only from a USB drive. This article details the steps I used to build the USB boot/installation drive and install Ubuntu 6.06 on the decTOP. There is another article -- with additional decTOP links -- here on installing Ubuntu 6.06 on the decTOP with the aid of a Windows system. Fortunately ;), I run Mac OS X and Linux (Ubuntu 7.04), so that article didn't work for me. I did the installation of the Ubuntu 6.06 LTS Server Edition using my Ubuntu Linux box and a 1 GB USB flash drive -- although a 512 MB USB drive should work as well. - Download the Ubuntu 6.06 server ISO image from the Ubuntu download page. Depending on your plans for the decTOP, you might want to choose the desktop version. Unless you have already upgraded your decTOP's memory, however, you'll want to stick with the 6.06 releases.
- Install the mbr, mtools, and syslinux packages on the Linux system you'll be using to prepare the USB drive. If you run Ubuntu or some other Debian-derived system, the following commands may do the work for you.
apt-get install mbr
apt-get install mtools
apt-get install syslinux - Partition the USB drive with a single FAT-16 partition. I used the fdisk 'n' command to make the new primary partition 1. The fdisk 't' command can be used to change the partition type to FAT-16. My device name was /dev/sda.
fdisk /dev/sda - Make the FAT-16 partition the active partition. I used the fdisk 'a' command.
- Install a master boot record on the USB drive.
install-mbr /dev/sda - Install syslinux on the USB drive. Note that the USB drive should not be mounted when you do this.
syslinux -s /dev/sda1 - Create a mountpoint and mount the ubuntu ISO image using the loopback device.
mkdir /iso
mount -o loop -t iso9660 ubuntu.iso /iso - Create a mountpoint and mount the USB flash drive.
mkdir /usb
mount /dev/sda1 /usb - Copy the contents of the ISO image to the USB drive. This will take some time.
cd /iso
cp -r . /usb/ - Copy the /usb/dists/dapper directory into a new /usb/dists/stable directory.
cd /usb/dists/
cp -r dapper/* stable - Copy several files from /usb/install to the /usb root directory.
cp /usb/install/vmlinuz /usb/
cp /usb/install/mt86plus /usb/
cp /usb/install/initrd.gz /usb/ - Install the following text into a file named syslinux.cfg in the /usb root directory.
default vmlinuz
append initrd=initrd.gz ramdisk_size=24000 root=/dev/ram rw - Flush all writes, unmount, and remove the USB drive. After the sync step, wait for all of the data to be written to the USB drive.
sync;sync
umount /usb - Connect the ethernet adapter to the decTOP and connect it to your network to allow automatic configuration of the network interface.
- Insert the USB drive into the decTOP and power it up. The decTOP should automatically boot from the USB drive and start the Ubuntu installation.
- Answer only the first two questions concerning language selection and go to the next step, below.
- Press Alt-F2 (hold down the Alt key and press the F2 function key) to open a shell. Then press enter to start the shell.
- Create a /cdrom and a /dev/cdroms directory in the installation ramdisk
mkdir /cdrom /dev/cdroms - Go to the /dev/cdroms directory and build a symlink from /dev/sda1 (that is likely the device name of your USB boot partition) to /dev/cdroms/cdrom0.
cd /dev/cdroms
ln -s ../sda1/cdrom0 - While still in the shell, mount the USB drive to mimic an installation CD-ROM.
mount -t vfat /dev/cdroms/cdrom0 /cdrom - Return to the installation program with Alt-F1 and continue the installation.
From this point, the process should be identical to a routine CD-ROM installation. For a grand total of $140 and 8 watts of power consumption, I now have a near-silent Linux server running 24/7. You can telnet to it here and marvel at its blinding speed running a 250,000-sector Space Tyrant game. |
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| | mail this link | permapage | score:9746 | -Ray, August 16, 2007 |
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Install a Mail Server with Antivirus and Antispam in minutes |
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This article illustrates a situation where you need to set up your own mail server (be it your home mail server, or a small office one). It actually shows that, if using an integrated service mail server, anyone can do the job, all in a matter of minutes.
AXIGEN Mail Server, the solution chosen for this example, can send and receive e-mails securely via "mydomain.com" and is able to retrieve them in a WebMail interface - this means that it includes all mail services needed for a fully functional mail server (SMTP, IMAP, POP3, WebMail, WebAdmin).
To get an idea of the amount of time you can spare by installing such a solution, just think of all the different open source applications you would need to install instead (i.e. an MTA, Squirrelmail for Webmail, QmailAdmin for web configuration, Courier for IMAP and POP3 and many others.)
AXIGEN Mail Server can virtually integrate with any Antivirus/Antispam application and it comes with built-in connectors ClamAV Antivirus and SpamAssassin. The second part of this article shows you how to install these applications and configure these connectors for use with AXIGEN.
Thus, at the end of this process which can take up half an hour at most, you will not only have your mail server up and running, but also virus and spam protection for your incoming and outgoing mail traffic.
AXIGEN runs on several Linux distributions (Gentoo, Redhat/Fedora Core, Slackware, Debian, Ubuntu, Mandrake/Mandriva, SUSE), on BSD versions (FreeBSD, OpenBSD and NetBSD) and on Solaris but for the purpose of this article, let's suppose you are setting up your mail system on a Fedora Core 6 platform.In five easy steps, you will have your server installed, your primary domain running and access to the Web configuration interface (WebAdmin).
1. Download / unpack corresponding package
Download AXIGEN rpm package from the AXIGEN website (packages are available as 30 day evaluation versions). Save the corresponding package for Fedora Core 6 "axigen-2.0.4.i386.rpm.gcc4.tar.gz" on your local machine and unpack the file, by issuing in the same directory as the download file:
tar xzvf axigen-2.0.4.i386.rpm.gcc4.tar.gz
2. Install command
Then, in order to install the RPM package, issue (while logged in as root) the following command, from the same directory as the rpm file:
rpm -ivh axigen-2.0.4.gcc4-1.i386.rpm This will create the entire directory structure needed for AXIGEN to run. After the installation, no daemons or related application will be started.
3. Configuration options
AXIGEN provides several configuration options (configuration file, Command Line Interface), but the most intuitive and comprehensive one is WebAdmin, the Web configuration interface.
The corresponding WebAdmin service is enabled by default, as well as the other default services: IMAP, Logging, POP3, Processing and SMTP.
4. Initial configuration
The first configuration steps take place using the configuration wizard. You will set the administrator's password, select which services are started and what interfaces will be used. In this stage of the setup you also create the primary domain that your server will use.
The wizard can be run by issuing the following command in the console right after the installation of the package has finished:
/opt/axigen/bin/axigen-cfg-wizard NOTE: You have to make sure you do not start the mail server before the initial configuration.
5. Start AXIGEN
You can then start AXIGEN, using its initscript, by issuing this command:
/etc/init.d/axigen start Now that your server is running, you can connect the antivirus and anti-spam applications. By default, AXIGEN comes with connectors for the ClamAV Antivirus and SpamAssasin Antispam application. The setup process below describes how to make these two applications work with AXIGEN. However, note that AXIGEN implements a proprietary filter scripting language that allows you to implement connectors for any third party Antivirus and Antispam applications.
Connecting to ClamAV
A. Install ClamAV (daemon), on the same machine on which AXIGEN Mail Server is installed. Follow these steps in order to configure ClamAv for use with AXIGEN and start the clamd daemon.
1. Install clamav-server, using yum (Yellow Dog Updater, Modified):
yum install clamav-server 2. Copy the sample config file shipped with clamav-server:
cp /usr/share/doc/clamav-server-*/clamd.conf /etc/clamd.d/axigen.conf 3. Edit: /etc/clamd.d/axigen.conf
# comment out the Example line
# Example
# insert/modify the following lines:
LogFile /var/log/clamd.axigen
PidFile /var/run/clamd.axigen/clamd.pid
LocalSocket /var/run/clamd.axigen/clamd.sock
User axigen 4. Create a link to the clamd binary:
ln -s /usr/sbin/clamd /usr/sbin/clamd.axigen 5. Create the run directory, where the PID file and clamd socket will be stored, and change its permissions:
mkdir -p /var/run/clamd.axigen chown axigen:axigen /var/run/clamd.axigen 6. Create and setup the initscript:
cp /usr/share/doc/clamav-server-*/clamd.init /etc/init.d/clamd.axigen
chmod 755 /etc/init.d/clamd.axigen /sbin/chkconfig clamd.axigen on
7. Edit: /etc/init.d/clamd.axigen and modify the following lines, as specified below:
# description: The clamd server running for axigen CLAMD_SERVICE=axigen 8. Finally, start the clamd daemon:
/etc/init.d/clamd.axigen
B. Configure AXIGEN antivirus filter at server level using WebAdmin
In order to activate the ClamAV filter, go through the following steps:
In the "Server" context, click on the Add new filter button. This will open up and display the Active Filter list. It is empty right now, so we need to add the clamav filter to the list.
In the Priority field, enter a priority between 0 and 500 (a filter with priority 0 will be applied first and the one with 500, last).
Important - the domain-level filters have the priority limited to range 100-400 and the user-level filters are limited to the 200-300 range. A value of "10" should be fine, leaving you space to apply some other future filters before this one.
After setting the filter priority, select the socket value from in the Filter type dropdown list and the clamav value from the Filter Name list.
In the Apply on checklist, select the relay option, to apply the filter on outgoing mails. To make sure you scan both incoming and outgoing mails, you have to create the filter and select both values, local and relay.
In AXIGEN, it is possible to enable filters either at domain or user level, in the corresponding WebAdmin tabs. The filters activated at server level will be automatically applied for all domains and accounts. However, you have the possibility to add additional filters at domain or account level.
Connecting to SpamAssasin
The process for Connecting SpamAssassin is similar and even less time-consuming as no configurations are necessary after the product installation.
C. Install SpamAssassin using the yum application:
yum install spamassassin No further configurations are necessary.
D. Configure SpamAssassin at server level, using Webadmin
The connector for SpamAssassin is a socket filter for AXIGEN, so the configuration procedure is the same as for ClamAV. The difference would be that for SpamAssassin, a TCP socket is more likely to be used.
Also, when activating the SpamAssassin filter, you need to keep in mind the following:
- Enter a different priority value for the SpamAssasin filter (if you have chosen 10 for ClamAV, choose a higher value for SpamAssassin in order to apply this filter after ClamAV in the filtering chain)
- Select the corresponding filter name, spamassassin in the Filter name list
Access AXIGEN WebMail
At this step of the way, your mail server is ready to go, and you can also you can access the AXIGEN WebMail to send and receive test messages. Then, use the full email address and password to log on to AXIGEN WebMail, at the default address: http://127.0.0.1:8000, or use the address you specified in the initial configuration phase when you ran the setup wizard.
Now you're really done: you can securely send and receive messages from your home domain and easily make any further configurations, to accommodate your specific network requirements. As you have seen, installing all mail services from one single executable and an intuitive Web configuration interface make things a lot easier and a lot less time-consuming.
Authors:
Liviu Anghel, Chief Security Officer, Gecad Technologies
Ciprian Negrila, Technical Support Engineer, Gecad Technologies
read more... |
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| | mail this link | permapage | score:9625 | -Kayla Vincent, February 6, 2007 |
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MiniLesson: An introduction to Linux in ten commands |
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This tutorial is the first in a series of introductory Linux lessons. This first article will cover navigating around a Linux filesystem along with a brief passage -- with examples -- on using ten of the most essential GNU/Linux commands.
You should have access to a Linux system in order to perform the example commands as we progress through the tutorial. If you don't have a dedicated Linux box, you can use a Live Linux CD-ROM-based distribution such as Knoppix. Knoppix will let you run Linux directly from the CD without modifying anything on your hard drive.
Once you're logged in to a Linux system, open a terminal session. Each of the commands covered here will be typed directly into a command line terminal window. Under Red Hat Linux, terminal is found in the 'system tools' section of the menu. (Your system may, alternatively, have a terminal program called 'konsole', 'xterm', or 'shell'. Look around your system for a menu with 'tools' or 'utilities' in the name if necessary.)
pwd
The first command we will use is 'pwd' -- which stands for 'print working directory'. The pwd command shows you your current position within the Linux filesystem. The position is known as your 'current working directory'. Type pwd now. The example below shows my command prompt and the pwd command followed by the output from the pwd command:
[rayy@barton0 rayy]$ pwd
/home/rayy
[rayy@barton0 rayy]$ From the output (/home/rayy) we can tell that I am in my 'home directory' -- the directory where I keep my personal files and the directory where I always start out in a new session.
ls
The ls command lets you list files. For example, here is the (shortened) output of an ls command on my system:
[rayy@barton0 code]$ ls
artdir countdir machine
tsardir sortdir
[rayy@barton0 code]$ Alternatively, you can get a 'long listing' that shows file sizes, timestamp, ownership, and permissions as follows:
[rayy@barton0 code]$ ls -l
drwxr-xr-x 2 rayy rayy 4096 Feb 3 2002 artdir
drwxr-xr-x 2 rayy rayy 4096 Feb 3 2002 countdir
drwxr-xr-x 2 rayy rayy 4096 Feb 3 2002 machine
drwxr-xr-x 2 rayy rayy 4096 Feb 3 2002 sortdir
drwxr-xr-x 2 rayy rayy 4096 Feb 3 2002 tsardir
[rayy@barton0 code]$ You can also supply a target directory to the ls command. For example, to view the contents of the /tmp directory, I enter the following:
[rayy@barton0 code]$ ls /tmp
flp kde-rayy mcop-rayy
[rayy@barton0 code]$ For more information on the ls command you can reference the manual page for ls with the following command:
[rayy@barton0 code]$ man ls cd
This next command, 'cd', lets you change your current working directory. for example, you can change your current working directory to /usr/bin by entering the following command:
[rayy@barton0 rayy]$ cd /usr/bin
[rayy@barton0 bin]$ Note that after I entered the cd command, my command prompt changed to reflect the change in the last node of my current working directory. Your command prompt may not be configured to do that.
Change your current working directory to /usr/bin now and enter the ls command.
[rayy@barton0 code]$ cd /usr/bin
[rayy@barton0 bin]$ ls
addr2line mcheck
addr2name.awk mcomp
addresses mcookie
.
.
.
[rayy@barton0 bin]$ The preceding is a partial listing. There are many, many files in the /usr/bin directory on most Linux systems.
file
If you have a background in Windows or are familiar with DOS, you are used to file extensions that signify the file type. Linux (and Unix) have no such requirement. That is, an executable program can be named anything. Therefore, a handy command is supplied with Linux named 'file'. For example, I have a file named 'sample.c' in my code directory. I can learn a bit about that file by entering the following command:
[rayy@barton0 code]$ file sample.c
sample.c: C++ program text
[rayy@barton0 code]$ Alternatively, I can use the '*' wildcard -- which represents all filenames -- to examine all of my code files at once. The following is a shortened example:
[rayy@barton0 code]$ file *
bbsdir: directory
code.tar: GNU tar archive
genart.c: ASCII C program text
sample.c: C++ program text
xor: ELF 32-bit LSB executable
[rayy@barton0 code]$ The file command can be very useful to avoid minor annoyances -- such as when using one of the following three commands.
cat
The cat command is useful for concatenating multiple files -- or just for dumping a single text file to the screen. Before you use the cat command to dump a file to the screen, use the file command to make sure it's some variety of text file such as ascii text, commands/text, C source code, html/text, etc. The following is a shortened example of using file and cat to identify and dump a text file:
[rayy@barton0 code]$ file xor.c
xor.c: ASCII C program text
[rayy@barton0 code]$ cat xor.c
main()
{
int x;
unsigned char buff[128],
.
.
.
[rayy@barton0 code]$ more
The more command is useful when a text file is larger than a single screen. The following is a shortened example of using more to view a large C program:
[rayy@barton0 code]$ more xor.c
main()
{
int x;
unsigned char buff[128],
.
.
.
printf("n%sn",buff1);
printf("n%sn",buff2);
}
--More--(29%) Note the '--More--(29%)' at the end of the screen. That means that 29% of the file is above that line, implying that another 71% of the file is below. Press the space bar to page through the file, a screenful at a time. Press the b key to back up. If you finish looking before reaching the end of the file, press the q key to quit.
grep
The grep command, short for 'get regular expression and print', is useful for finding occurances of a particular string in a text file. To find the 'printf' statements in the example C program above, enter the following command:
[rayy@barton0 code]$ grep printf xor.c
printf("n%sn",buff1);
printf("n%sn",buff2);
[rayy@barton0 code]$ The grep command has far more capability than I describe here and, as usual, enter [rayy@barton0 code]$ man grep for more information.
cp
The cp command will let you copy files. Unlike the commands used above, this one includes a hazard; if you copy filename1 to filename2 and filename2 already exists, you will destroy the original filename2 file. Use cp with caution!
To make a duplicate copy of my xor.c file I could enter the following command:
[rayy@barton0 code]$ cp xor.c xor.c.bak
[rayy@barton0 code]$ ls xor.c*
xor.c xor.c.bak
[rayy@barton0 code]$ Note that the cp command returned no output -- I had to enter an ls command to see the results of the copy. [By adding the * wildcard to the original filename, I asked for a listing of all files that started with xor.c -- including those with no additional characters in the name.]
rm
The rm command is used for removing files. To remove the duplicate file I created in the cp command example, I would enter the following:
[rayy@barton0 code]$ rm xor.c.bak
[rayy@barton0 code]$ ls xor.c*
xor.c
[rayy@barton0 code]$ Again, note the absense of any feedback from the rm command. I had to enter an ls command to verify that the xor.c.bak file had really been removed.
As with other commands, rm can remove multiple files at once when used with wildcards or with the -r (recursive) option. See the man page for more information on rm.
mkdir/rmdir
Ok, this is really two commands, but they are complementary. Use the mkdir command to make a new directory and use the rmdir command to remove an empty directory. For example:
[rayy@barton0 tmp]$ mkdir testdir
[rayy@barton0 tmp]$ ls
testdir
[rayy@barton0 tmp]$ rmdir testdir
[rayy@barton0 tmp]$ ls
[rayy@barton0 tmp]$ In the preceding series of commands I first created a new directory named 'testdir'. I then used the ls command to verify its presence. Then, I removed 'testdir' and verified that it was gone by using ls again.
For more information on the commands covered in this article, take a look at the general commands man pages over at the LinuxQuestions.org website. |
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| | mail this link | permapage | score:9551 | -Ray, February 19, 2004 (Updated: April 18, 2007) |
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Scripting: A parallel Linux backup script |
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This example bash shell script demonstrates a simple method of creating backups of multiple filesystems to multiple tape devices simultaneously. While the script presented writes to four tape drives in parallel, it can easily be modified to write to other device types and to create a different number of backup streams. The script is set up for the bash shell under Linux, but modifying it for another variety of Unix should simply be a matter of changing the locations of utility files such as tar, echo, cp, and sleep.
The script can be downloaded from http://librenix.com/scripts/par.tar.sh. Download the file now and load it into an editor as this article will refer to it frequently. Also, you may want to modify bits of it to match your filesystem names and your devices.
The first line of the script looks like this:
#!/bin/bash If the bash shell isn’t in the /bin directory on your system, you’ll need to modify this line. Enter the command which bash now to verify the location of bash. My Fedora Linux system and my Mac OS X system both have bash in /bin, but my FreeBSD system does not. If you have a non-Linux flavor of Unix, you’ll probably need to use the ‘which’ command to verify the locations of each command used in the script. The commands used are:
bash
cd
sleep
echo
date
tar
wait
ls
wc Note that ‘wait’ and ‘cd’ are usually implemented as internal shell commands and may not have external commands associated with them. If that is true for your system, leave ‘cd’ and ‘wait’ with no directory prefix just as they are in the original script.
Now, the first command in the script resets the current working directory to ‘/’:
cd / Since the script precedes each directory to be backed up with a ‘.’ to represent the current working directory, starting out at ‘/’ is necessary. The reason for this precaution is that some implementations of the tar command will only load files from a tar archive into the exact directory that was specified when the file was backed up. By prefixing the names with a ‘.’ we preserve the ability to recover the files into any subdirectory we want, without overwriting the original files.
Immediately after the ‘cd /’ command is where you would put any commands to shut down all services that must be quieted prior to a backup. The example script has a (commented out) command to initiate an Oracle database shutdown followed by a ‘sleep’ command to allow time for the shutdown to complete. The example database shutdown and the following delay probably don’t apply to your system. Obviously, you’ll have to add commands yourself to stop any applications that might interfere with the backup.
Next, we use the ‘date’ command to create two sets of four tiny files to stick at the start and end of each tape. Note that the presence of a ‘date.#’ file at the beginning of each tape lets you quickly find out when a tape was created and on which drive. The ‘zzzz.#’ files, appended to the end of each tape, only serve to let you easily verify that a backup completed without overrunning the end of the tape.
Next, we start the four actual ‘tar’ backup commands, each with sample directories named ‘./dir1’, ‘./dir2’, etc. Of course, you’ll need to modify the list of directories to match the actual directories you wish to back up. Note that you’ll probably want to balance the directory sizes so that all of the largest directores aren’t on the same tape. Also, note that each ‘tar’ command is run in the background and logs to a tar.#.log file in the /tmp directory. Obviously, you might want to put the logfiles somewhere else.
After each ‘tar’ command there is an entry like this: ‘TASK=$0’, or ‘TASK=$1’. These arbitrarily-named ‘TASK’ variables are used to store the process ID of each ‘tar’ command so that the script can wait for them with the four ‘wait’ commands that follow in the next block of code. There, we have the four ‘wait’ commands waiting on the $TASK0, etc, variables. (The addition of the ‘$’ to each TASK# shell variable is not a typo -- it’s necessary to read back the contents of the variable.)
Next, after the script has waited for the completion of each of the four ‘tar’ commands, it appends some information to a history file for later reference. It stores the date of the backup, the filesize of the logfile, and the number of files backed up on each tape to each of four history files. While the script will overwrite the logfiles (tar.#.log) each time it is run, it will append these three lines to each of the four history files (tar.#.history).
The final steps in the script are commented out. Those are the commands necessary to restart any applications that were brought down for the backup. Again, in the example we assume an Oracle database needs to be restarted. You’ll need to add the commands necessary to start any applications that were stopped at the beginning of the script. |
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| | mail this link | permapage | score:9532 | -Ray, April 10, 2005 |
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