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How to disable spamfilter- and antivirus functions in ISPConfig 3

Wednesday, July 14, 2010 - posted by Till

If you use a mailserver wil very low ram (< 500 MB) and a slow CPU then it might be nescessary to disable the spam- and antivirus filter functions in ISPConfig 3 as amavisd and clamav might be too heavy for your server hardware. The steps to disable clamav and amavisd are:

Edit postfix main.cf file

vi /etc/postfix/main.cf

and comment out these lines by adding a "#" in front of them:

# content_filter = amavis:[127.0.0.1]:10024
# receive_override_options = no_address_mappings

Then restart postfix:

/etc/init.d/postfix restart

Now stop and disable the services. The following commands are for Debian and Ubuntu, the commands for other Linux distributions may vary

/etc/init.d/clamav-daemon stop
/etc/init.d/clamav-freshclam stop
/etc/init.d/amavis stop

update-rc.d -f clamav-daemon remove
update-rc.d -f clamav-freshclam remove
update-rc.d -f amavis remove

P The normal mail receive and send functions will still work after this modification. But please be aware that disabling amavisd and clamav will disable all spam- and antivirus filtering so that the spamfiltering options that can be configured in the ispconfig interface will have any effect on mail delivery and no spam and viruses will get filtered.

The changes in postfix main.cf will get overwitten by a ispconfig software update when you select to reconfigure services during upadte, so you should comment out the lines again after you install a ispconfig update.

There is a handy Thunderbird extension named "Auto zip" available that compresses email attachments as .zip files automatically, So you dont have to compress the files manually anymore before you attach them to the email.

Thunderbird extension download:

https://addons.mozilla.org/en/thunderbird/addon/4003

Sadly, the official version of the plugin works only for thunderbird 2. But a few users offer already patched versions for Thunderbird 3 (see links in the comments). Please be aware that using such a patched version has the risk that it might contain malicious code.)

https://addons.mozilla.org/de/thunderbird/reviews/display/4003

How to block access to a server by IP address on Linux

Tuesday, July 6, 2010 - posted by Till

Sometimes you might want to block connects to your server by IP address. E.g. when someone tries to attack your system. This can be done in several different ways, e.g. with iptables (firewall) rules or by setting up a reject route. Using iptables sometimes causes conflicts with installed firewalls so that I will use the route command here. The command is:

/sbin/route add -host 192.168.0.123 reject

Replace 192.168.0.123 with the IP address that you want to block and execute the command as root user on the shell.

How to enable the new multisite feature in WordPress 3.0

Sunday, June 20, 2010 - posted by Till

If you recently updated to or installed WordPress 3.0, you might wonder where the menu for Multisite feature is. By default, these new functions are disabled after a WordPress update, to enable them, edit the file wp-config.php and add the line

define(‘WP_ALLOW_MULTISITE’, true);

On your next login, you will see a new menu labeled "Super Admin" which contains the functions to add new sites to wordpress.

The pure-ftpd package that comes with Debian 5.0 (Lenny) does not start in a OpenVZ virtual machine as it is compiled with "capabilities". This tutorial describes the steps to build a pure-ftpd Debian package with capabilities disabled:

Make a temporary directory

mkdir /usr/src/pure-ftpd
cd /usr/src/pure-ftpd

Download the source package for pure-ftpd

apt-get source pure-ftpd
apt-get build-dep pure-ftpd

Edit the rules file and add the switch "--without-capabilities"

cd pure-ftpd-1.0.21/debian
nano rules

Change the line:

optflags=--with-everything --with-largefile --with-pam --with-privsep --with-tls

to (one Line!):

optflags=--with-everything --with-largefile --with-pam --with-privsep --with-tls --without-capabilities

Build the Debian (.deb) package

cd ..
dpkg-buildpackage -uc -b

and install it

cd ..
dpkg -i pure-ftpd-common_1.0.21-11.4_all.deb pure-ftpd-mysql_1.0.21-11.4_i386.deb
/etc/init.d/pure-ftpd-mysql restart

To prevent that apt overwrites these manually compiled packages with the default packages from the Debian repositorys, execute these commands:

echo 'pure-ftpd-common hold' | dpkg --set-selections
echo 'pure-ftpd-mysql hold' | dpkg --set-selections

This tutorial is based on the german tutorial from planet_fox

How to update Spamassassin on ISPConfig 2

Thursday, May 27, 2010 - posted by Till

The spamassassin installation on a ISPConfig 2 server is normally updated together with ISPConfig. Here are the steps iIf you want to update spamassassin manually without updating ISPConfig 2:

Download the latest Spamassassin sources and unpack the tar.gz file

cd /tmp
wget http://ftp.fernuni-hagen.de/ftp-dir/pub/mirrors/\
www.apache.org/spamassassin/source/Mail-SpamAssassin-3.3.1.tar.gz
tar xfz Mail-SpamAssassin-3.3.1.tar.gz

Configure, make and install spamassassin

cd Mail-SpamAssassin-3.3.1
perl Makefile.PL PREFIX=/home/admispconfig/ispconfig/tools/\
spamassassin/usr SYSCONFDIR=/home/admispconfig/ispconfig/\
tools/spamassassin/etc
make
make install

Cleanup

cd ..
rm -f Mail-SpamAssassin-3.3.1.tar.gz
rm -rf Mail-SpamAssassin-3.3.1

How to enable port 587 (submission) in postfix

Monday, April 26, 2010 - posted by Till

Some internet access providers have port 25 disabled in their routers to prevent spam. If you run your own mailserver in a datacenter, you might have to enable the submission port (587) in postfix to be able to send emails from your local email client to your own mailserver.

To enable port 587, edit the file /etc/postfix/master.cf

vi /etc/postfix/master.cf

and remove the # in front of the line:

#submission inet n - n - - smtpd

so that it looks like this:

submission inet n - n - - smtpd

and restart postfix:

/etc/init.d/postfix restart

NiceToHave tool for monitoring from the command line with Saidar

Monday, April 19, 2010 - posted by andreea

With Saidar you can display and view all your system statistics.

For an installation in Ubuntu or Debian you can install this with following command:

sudo apt-get install saidar

After having installed it, you can type in the command saidar:

saidar

Now you see in the following screen a complete view of your CPU, processes, load, memory, swap network I/O and disks I/O along with their free space.

The following options are supported:

-d    (Wait DELAY seconds between updates (default 3))

-v   (Prints the version number)

-h   (Display help and exits)

That's it! Thanks to Planetfox for this tipp.

As of today, all ClamAV 0.94 or older installs will stop working. The Debian project has not released updates for their current stable release (5.0) yet to solve this, but there is a workaround. The Debain volatile project provides newer clamav versions. The installation steps to install ClamAV 0.95.3 on Debian lenny are:

1) Add the debian volatile repository to the sources list:

echo "deb http://volatile.debian.org/debian-volatile lenny/volatile main contrib non-free" >> /etc/apt/sources.list

2) Update the sources and install the new clamav package:

apt-get update
apt-get install clamav
apt-get -u upgrade

3) If you use amavisd-new (e.g. if you use a ISPConfig 3 server) then restart amavisd:

/etc/init.d/amavis restart

How to save the music from a youtube video as mp3 file

Wednesday, April 14, 2010 - posted by Till

Have you ever wanted to save the sound from a youtube video on your harddisk as mp3 file? There is a handy Firefox plugin named "Youtube to mp3" available for that. Open the following link in the Firefox webbrowser:

https://addons.mozilla.org/de/firefox/addon/11047/

and click on the "add to Firefox" link to install the plugin. Then restart firefox to activate the plugin.