Linux: January 2006 Archives

I mentioned a handy little tool I came across for installing a variety of useful apps on my ubuntu laptop recently. Paul O'Malley has pointed me in the direction of an alternative called (strangely enough) Easy Ubuntu It doesn't offer as wide a selection of applications, but it probably does more than enough for most people:

Easy Ubuntu allows you to:

• Add extra repositories for installing a lot of additional software.
• Install multimedia codecs for reading all videos, musics and DVDs.
• Activate the "audio preview" feature in Nautilus.
• Install the most needed Firefox plugins: Flash, Java, Real, videos. Adds Microsoft fonts, GNOME's Firefox buttons, officials Firefox icons.
• Install archiving support for RAR and ACE.
• Install the most used peer-to-peer softwares: aMule (a clone of eMule) and Azureus (for Bittorent).
• Install the Skype voice-over-IP software. (Warning: at this time Skype is not packaged for Breezy so install don't work)
• Num lock: Active the num lock at system startup.
• Replace the GNOME foot logo with Ubuntu's logo.
• Install the NVIDIA or ATI driver for 3D support.

More information on its creator's site

This site and server runs on open source software. I'm writing this blog entry using open source software. Our business runs predominately on open source software.

This howto was written in order to help users of DirectAdmin install and correctly configure MailScanner with Exim.

 It is based on several years experience working with MailScanner and has been used in the installation of production servers running a variety of rpm based linux distributions including:
 RedHat 9
Fedora
Centos
WhiteBox

While every effort has been made to make this howto as comprehensive and easy to follow as possible the author welcomes feedback.

Before you start you should install vim.

On most Red Hat Enterprise clones, such as Centos, the following command should work:

yum install vim-enhanced

I would recommend creating a directory such as /home/installstuff or similar for any files / packages related to your MailScanner setup.

The next step is to install SpamAssassin.

There are a number of ways of doing this, however the developer of MailScanner has put together an easy to use package that will install all the required perl Modules for you. It can be downloaded here.

NB: As of SA 3.1 the licensing has changed for some of the plugins. You will need to enable razor etc., in the *.pre files in the /etc/mail/spamassassin directory

Now to install MailScanner.

First download the MailScanner rpm tarball from the website.

There are usually two versions available – stable and beta.
wget location of file tar -zxvf MailScanner file cd MailScanner directory ./install.sh

For example, to download and install the current beta version at time of writing the command would be:

wget http://www.sng.ecs.soton.ac.uk/mailscanner/files/4/rpm/MailScanner-4.50.8-1.rpm.tar.gz tar -zxvf MailScanner-4.50.8-1.rpm.tar.gz cd MailScanner-4.50.8-1 ./install.sh

Relax and have a cup of coffee.

Once the install is finished you can proceed with the setup of MailScanner to work with exim.

You need to change the permissions on the MailScanner spool directory:

chown -R mail.mail /var/spool/MailScanner

MailScanner works by running two processes of the MTA.
One listens for SMTP connections (inbound mail) while the other processes outbound mail. If you think of it like this:

mail > exim > MailScanner > exim

Mail is passed from one exim process to the other via MailScanner, where all the content checks are conducted. For this reason you need to have two .conf files for exim. One for each exim process.

Always create backups!

cp /etc/exim.conf /etc/exim.back

Make a copy to handle outbound mail:
 
cp /etc/exim.conf /etc/exim_send.conf

Edit the exim.conf file:
 
vim /etc/exim.conf

and add the following lines in the main part of the configuration:
#Added for MailScanner mail queues and logging
spool_directory = /var/spool/exim.in queue_only = true
queue_only_override = false
log_file_path = /var/spool/exim/msglog/%slog

 MailScanner comes with its own startup script, so you can safely get rid of the original one:

 #cd /etc/init.d/ cp exim exim.orig;chmod -x exim.orig rm exim

However, DirectAdmin will check for the exim file, so we create a symlink to fool it:

ln -s MailScanner exim

NB: You may need to do this again if a DirectAdmin update installs a new exim init script

Create the following directories:
mkdir /var/spool/exim.in
mkdir /var/spool/exim.in/input
mkdir /var/spool/exim.in/data
mkdir /var/spool/exim.in/db

then fix the ownership:

chown -R mail.mail /var/spool/exim.in/

Now you need to customise your MailScanner.conf both for your particular server and to let it know that it is running exim:
Open MailScanner.conf in vim as follows:

vim /etc/MailScanner/MailScanner.conf

The file is very well documented. Please read it!

You should edit the following settings:

%org-name% = servername
%org-long-name% = Your Company Name .
%web-site% = www.yourwebaddress.tld

Now to tell it about your exim configuration.

Find the following lines in MailScanner.conf and edit as indicated:
#Run As User = mail
#Run As User = postfix
Run As User = mail # Group to run as (not normally used for sendmail)
#Run As Group = mail
#Run As Group = postfix
Run As Group = mail
Incoming Queue Dir = /var/spool/exim.in/input
Outgoing Queue Dir = /var/spool/exim/input
Sendmail = /usr/sbin/exim -C /etc/exim.conf
Sendmail2 = /usr/sbin/exim -C /etc/exim_send.conf
MTA = exim (as opposed to sendmail)

You can further tweak your MailScanner settings later on.

Some more changes are needed to finalise your setup.

MailScanner should autodetect exim, but you need to make a number of changes to /etc/sysconfig/MailScanner do the following:

mkdir /usr/local/exim/
mkdir /usr/local/exim/bin

make the following symlinks:

ln -s /etc/exim_send.conf /usr/local/exim/exim_send.conf
ln -s /etc/exim.conf /usr/local/exim/configure
ln -s /usr/sbin/exim /usr/local/exim/exim
ln -s /usr/sbin/exim /usr/local/exim/bin/exim

To test if it is working properly or not issue the following command:

/etc/init.d/MailScanner restart;tail -f /var/log/maillog

You should see something like the following:

Shutting down MailScanner daemons: MailScanner: [ OK ]
incoming exim: [ OK ]
outgoing exim: [ OK ]
Starting MailScanner daemons:
incoming exim: [ OK ]
outgoing exim: [ OK ]
MailScanner: [ OK ]

Keep an eye on the logs for a few minutes. If anything is wrong you should see an error in them.

In order to increase your setup's effectiveness against spam and viruses you can now tweak your settings.

As I already mentioned, the MailScanner.conf file is very well commented, so read what the configuration options are doing before you actually change them on a production system.

This method of setting up MailScanner has been tried and tested.

It works for us, however any feedback is always appreciated.

I never thought I'd see the day that I'd be looking into running OS X under linux or windows, but that's the position I've found myself in.

This month's Computers in Business (the IT supplement from the Sunday Business Post) has an interesting article by Barry McCall which covers the "marriage" of open and closed source solutions in the corporate environment. Some of his reflections are quite incisive:

Some competing Linux distributors are blindly following a pure open source path while some proprietary vendors are doggedly fighting the advancing tide of open source. It is hard to see either succeeding in the face of a growing move to mixed-source strategies

The full article is definitely worth reading: Best of Both Worlds