Archive for the ‘Linux & Unix’ Category
Get a list of all virtual hosts which are defined in all apache configuration files
Have you ever searched where the virtual host of a website is defined in the apache config files? There is a handy option of the apache2ctl script which might help then. When you run the command:
apache2ctl -S
on the shell, you will get a list of all virtual hosts and default servers incl. the line number where it is defined. Example:
~# apache2ctl -S VirtualHost configuration: wildcard NameVirtualHosts and _default_ servers: *:8080 is a NameVirtualHost default server ispconfig.local (/etc/apache2/sites-enabled/000-ispconfig.vhost:10) port 8080 namevhost ispconfig.local (/etc/apache2/sites-enabled/000-ispconfig.vhost:10) *:8081 is a NameVirtualHost default server ispconfig.local (/etc/apache2/sites-enabled/000-apps.vhost:10) port 8081 namevhost ispconfig.local (/etc/apache2/sites-enabled/000-apps.vhost:10) *:80 is a NameVirtualHost default server ispconfig.local (/etc/apache2/sites-enabled/000-default:1) port 80 namevhost ispconfig.local (/etc/apache2/sites-enabled/000-default:1) port 80 namevhost example.com (/etc/apache2/sites-enabled/example.com.vhost:7) Syntax OK
Thanks to Planetfox for this tipp.
How to disable Apache mod_security for a website in ISPConfig 3.
If you use mod_security on your server you might encounter that a website script is not compatible with mod_security. To disable mod_security (v2) for a website, add the following code into the apache directives field:
<IfModule mod_security2.c> SecRuleEngine Off </IfModule>
For the older mod_security 1 version, use these configuration directives:
<IfModule mod_security.c> SecFilterEngine Off </IfModule>
Thanks to Planetfox for this tipp.
How to remove old java versions from Windows
When you install the latest java runtime enviroment, it gets installed beside your existing java installation. With every java update, more space is used on the harddisk. To remove old java versions, there is a tool named JavaRa which can be downloaded here:
https://sourceforge.net/projects/javara/files/javara/JavaRa/JavaRa.zip/download
Unpack the JavaRa.zip file and double click on the JavaRa.exe to start JavaRa. Select the language:
and click on “Remove older versions”.
How to convert RPM software packages to Debian (.deb)
Maybe you had this problem already: you use Debian or Ubuntu Linux and a software package that you like to install is only available in RPM format. The solution is a handy tool called alien, which converts .rpm files to .deb. Installing alien:
apt-get install alien
Converting a rpm package to debian format:
alien --to-deb /tmp/mysoftwarefile.rpm
Conversions from .deb to rpm are also possible:
alien --to-rpm /tmp/mysoftwarefile.deb
How to force caching headers with apache and squid reverse proxy
If you use a squid reverse proxy in front of your apache webserver to reduce the load, it might happen that pages are not cached correctly because the website script running on the apache webserver sends wrong caching headers. I had this problem with a wordpress install, wordpress had always send pragma no-cache headers with the pages so squid reported a cache miss for every page request. A simple solution for this is to use apache mod_headers to delete the no chache header and replace it with a header for 10 minute cache period.
First, ensure that mod_herders is enabled. To do this in Debian and Ubuntu, run the command:
a2enmod headers
Then create a .htaccess file in the website root directoyr which contains the following lines:
Header unset Pragma Header set Cache-Control "must-revalidate, max-age=0, s-maxage=600" Header set Vary "Accept-Encoding"
How to Update ISPConfig 3
The ISPConfig update script is a easy way to update a ISPConfig 3 installation. If you want to backup the installation before, 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. In the next step, enter the mysql root password:
This application will update ISPConfig 3 on your server. MySQL root password []:
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.
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
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
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
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?
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.
How to use apt-file to find which .deb package contains a specific file
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