Archive for the ‘Linux & Unix’ Category

How to Update ISPConfig 3

Friday, February 19, 2010 posted by Till

The ISPConfig update script is a easy way to update a ISPConfig 3 installation. If you want to create a manual backup of ISPConfig, take a look at the instructions at the end of the article.

To update ISPConfig 3, login as root user on the shell of your server and run the command:

ispconfig_update.sh

>> Update

Please choose the update method. For production systems select 'stable'.
The update from svn is only for development systems and may break your current setup.

Select update method (stable,svn) [stable]:

You should always select "stable" on a production system. The "svn" version is only suitable for ISPConfig 3 development.

The updater will then check the version of your system, download the latest update and starts the update process.

This application will update ISPConfig 3 on your server.

Shall the script create a ISPConfig backup in /var/backup/ now? (yes,no) [yes]:

You should choose "yes" here. This will create a backup of the ISPConfig scripts (/usr/local/ispconfig), the /etc directory and the ISPC0nfig MySQL database in the directory /var/backup/

Creating backup of "/usr/local/ispconfig" directory...
Creating backup of "/etc" directory...
Checking ISPConfig database .. OK
Starting incremental database update.

The update script will then start to install incremental database updates for ISPConfig, if required.

Reconfigure Permissions in master database? (yes,no) [no]:

If this is a slave server in a multiserver setup, then choose "yes" here on at least one of the slave servers. For single server installations, choose 'no'. Then you were asked if the services shall be reconfigured:

Reconfigure Services? (yes,no) [yes]:

You should choose "yes" here, only if you modified your system configuration manually, it might be better to choose no. But in this case, new features in ISPConfig might not work or functions might stop working until you adjusted the config files manually. So its always a good choice to select 'yes' here. In the next step, select the ispconfig port:

ISPConfig Port [8080]:

Port 8080 is the default, if you have not changed it, press enter. Otherwise enter the port number and then press enter. As the last step, you wre asked if the crontab shall get reconfigured, you can select yes here by just pressing return.

Create new ISPConfig SSL certificate (yes,no) [no]:

If your SSL certificate for the ISPConfig interface has been expired and you want to renew it or if you want to enable SSL encryption for the ISPConfig interface, then choose "yes". If you dont need a new SSL certificate, take the default (no).

Reconfigure Crontab? (yes,no) [yes]:

The ISPConfig updater will then update the ispconfig files and restart services, if the configuration has been changed.

Backup before updates

(This backup procedure is now integrated into the ISPConfig updater and gets executed automatically when you choose to create a backup during update)

Before you update a software, it is always a good idea to backup all relevant data. This enables you to restore the software version that you had before in case of an error. The steps to create a backup of the ispconfig software and settings are:

Create a backup folder:

mkdir /home/backup
chmod 700 /home/backup
cd /home/backup

Backup the database

mysqldump -u root -p dbispconfig > dbispconfig.sql

Backup the ISPConfig software

tar pcfz ispconfig_software.tar.gz /usr/local/ispconfig

Backup the configuration files in /etc

tar pcfz etc.tar.gz /etc

This backup does not include the emails and website data.

Rerun the last command with sudo on the Linux shell

Friday, February 19, 2010 posted by Till

Have you ever executed a command on the shell and noticed the that you had to run it with sudo? Instead of typing the command again with "sudo" in front of it, just run:

sudo !!

which will execute the command that was run before with sudo. Thanks to Planetfox for this tipp.

Keep the spamassassin filter rules up to date in ISPConfig 3

Friday, February 5, 2010 posted by Till

To update the spamassassin rules regularily on your ISPConfig 3 server, add the following line to the root crontab by running:

crontab -e

then insert the following line:

23 4 */2 * * /usr/bin/sa-update --no-gpg &> /dev/null

and save the file. The path to the sa-update script is /usr/bin/sa-update on Ubuntu and Debian Linux, if you use a different linux distrubution, run the command:

which sa-update

to find the location of the sa-update script and adjust the path in the crontab line above so that it matches the path on your system.

How to kill processes in “D” state in Linux?

Tuesday, February 2, 2010 posted by Till

If a process is shown with process state "D" in tools like ps or top, then its a zombie process. Example:

ps axl | grep D

F   UID   PID  PPID PRI  NI    VSZ   RSS WCHAN  STAT TTY        TIME COMMAND
4   104  2579  9109  20   0   5024  2116 refrig D    ?          0:00 cleanup -z -t unix -u -c

Zombie processes can not be killed with the normal commands like "kill -9 PID", you will have to reboot the system to kill them.

Sometimes you need to know which debian package contains a specific file e.g. because you deleted a system file accidently or you try to install a new software that requires this file. The apt package management utility which is used in Debian and Ubuntu comes with a handy tool called apt-file which allows a saerch for filenames in the package database.

Install apt-file

apt-get install apt-file

Update the apt-file database

apt-file update

Search for a specific file name, e.g. "lcrypto"

apt-file search /bin/bash

apt-file search /bin/bash
bash: /bin/bash
bash: /usr/bin/bashbug
bash-minimal: /bin/bash-minimal
bash-static: /bin/bash-static
bashdb: /usr/bin/bashdb
mybashburn: /usr/bin/bashburn

Test the phising filter of your web browser

Wednesday, January 13, 2010 posted by Till

If you like to test if the phising filter of your webbrowser works, open the following URL of the mozilla test page in the browser:

You should get a result page that looks similar to this one if you use the Mozilla Firefox browser:

Make the gnome desktop in Ubuntu 9.10 to look like Windows XP

Thursday, January 7, 2010 posted by Till

The following steps describe the Installation of the XPGnome theme for Ubuntu Linux. Run the following commands in the Ubuntu Shell window to make Ubuntu look like Windows XP:

cd /tmp
wget http://ubuntu.online02.com/files/XP_Gnome.tar.gz
cd XP_Gnome
./InstallXpGnome.sh

Screenshots:

http://ubuntu.online02.com/node/14

Since january 1 2010, spamassassin is falsely marking non spam emails as spam due to an error in the regular expression of the FH_DATE_PAST_20XX rule.

Description of the bug:

https://secure.grepular.com/blog/index.php/2010/01/01/spamassassin-2010-bug/

To fix this, run the following command on the shell as root user:

sa-update

If you use the software ISPConfig 2 on your server, run this command:

/home/admispconfig/ispconfig/tools/spamassassin/usr/bin/sa-update

How to renew the SSL certificate for dovecot on CentOS

Wednesday, December 23, 2009 posted by Till

Make a backup of the old key and certificate file

mv /etc/ssl/certs/dovecot.pem /etc/ssl/certs/dovecot.pem.old
mv /etc/ssl/private/dovecot.key /etc/ssl/private/dovecot.key.old

Create the new SSL certificate

openssl genrsa -out /etc/ssl/private/dovecot.key 1024
openssl req -new -x509 -key /etc/ssl/private/dovecot.key -out /etc/ssl/certs/dovecot.pem -days 730

Restart Dovecot:

/etc/init.d/dovecot restart

Optimize MySQL performance with mysqltuner

Tuesday, December 22, 2009 posted by Till

The following tutorial describes the steps to optimize the performance of a MySQL database with the mysqltuner script.

Login to your server on the shell, then execute the following commands:

Download the mysqltuner script:

cd /usr/local/bin
wget http://mysqltuner.pl/mysqltuner.pl
chmod +x mysqltuner.pl

Run mysqltuner

/usr/local/bin/mysqltuner.pl

Then enter root as username and the mysql root password.

You will get a output similar to this:

root@v221:/usr/local/bin# /usr/local/bin/mysqltuner.pl

>>  MySQLTuner 1.0.1 - Major Hayden <[email protected]>
>>  Bug reports, feature requests, and downloads at http://mysqltuner.com/
>>  Run with '--help' for additional options and output filtering
Please enter your MySQL administrative login: root
Please enter your MySQL administrative password:

-------- General Statistics --------------------------------------------------
[--] Skipped version check for MySQLTuner script
[OK] Currently running supported MySQL version 5.0.51a-24+lenny2
[!!] Switch to 64-bit OS - MySQL cannot currently use all of your RAM

-------- Storage Engine Statistics -------------------------------------------
[--] Status: +Archive -BDB -Federated +InnoDB -ISAM -NDBCluster
[--] Data in MyISAM tables: 26M (Tables: 215)
[!!] InnoDB is enabled but isn't being used
[!!] Total fragmented tables: 33

-------- Performance Metrics -------------------------------------------------
[--] Up for: 96d 23h 3m 41s (10M q [1.239 qps], 686K conn, TX: 701M, RX: 1B)
[--] Reads / Writes: 44% / 56%
[--] Total buffers: 58.0M global + 2.6M per thread (100 max threads)
[OK] Maximum possible memory usage: 320.5M (12% of installed RAM)
[OK] Slow queries: 0% (20/10M)
[OK] Highest usage of available connections: 33% (33/100)
[OK] Key buffer size / total MyISAM indexes: 16.0M/8.5M
[OK] Key buffer hit rate: 99.9% (57M cached / 30K reads)
[OK] Query cache efficiency: 78.6% (5M cached / 6M selects)
[!!] Query cache prunes per day: 483
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 408K sorts)
[!!] Temporary tables created on disk: 36% (269K on disk / 745K total)
[OK] Thread cache hit rate: 99% (427 created / 686K connections)
[!!] Table cache hit rate: 2% (64 open / 3K opened)
[OK] Open file limit used: 11% (120/1K)
[OK] Table locks acquired immediately: 99% (3M immediate / 3M locks)

-------- Recommendations -----------------------------------------------------
General recommendations:
Add skip-innodb to MySQL configuration to disable InnoDB
Run OPTIMIZE TABLE to defragment tables for better performance
Enable the slow query log to troubleshoot bad queries
When making adjustments, make tmp_table_size/max_heap_table_size equal
Reduce your SELECT DISTINCT queries without LIMIT clauses
Increase table_cache gradually to avoid file descriptor limits
Variables to adjust:
query_cache_size (> 16M)
tmp_table_size (> 32M)
max_heap_table_size (> 16M)
table_cache (> 64)

The script recommends to adjust or add the following variables in the mysql my.cnf file. The location of my.cnf is normally /etc/my.cnf or /etc/mysql/my.cnf depending on the Linux distribution that is installed on your server.

Open the my.cnf file:

vi /etc/mysql/my.cnf

and increase or set the variables in the [mysqld] section of the file. Mine looks now like this:

[mysqld]
#
# * Basic Settings
#
user            = mysql
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
port            = 3306
basedir         = /usr
datadir         = /var/lib/mysql
tmpdir          = /tmp
language        = /usr/share/mysql/english
skip-external-locking
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
bind-address            = 127.0.0.1
#
# * Fine Tuning
#
key_buffer              = 16M
max_allowed_packet      = 16M
thread_stack            = 128K
thread_cache_size       = 8
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover          = BACKUP
#max_connections        = 100
table_cache            = 128
#thread_concurrency     = 10
#
# * Query Cache Configuration
#
query_cache_limit       = 1M

query_cache_size        = 32M
tmp_table_sizee        = 64M
max_heap_table_sizee        = 32M

Then save the file and restart mysql. After a few hours, rerun mysqltuner and check again if the values are fine now or if the have to be increased to a higher value.