How to get a list of all open ports on Windows 7, Vista and XP?

There is a small freeware Utility called CurrPorts from Nirsoft that displays all open ports on windows.

Download CurrPorts to your computer:

32Bit version:

64Bit version:

Unpack the .zip file and double click on the file cports.exe to start CurrPorts. The application will show you a list of all open ports and offers the ability to apply filters on the list.


How to reset the administrator password in ISPConfig 3

If you lost your ISPConfig 3 administrator password, you can reset it with the following SQL query.

UPDATE sys_user SET passwort = md5('admin') WHERE username = 'admin';

The SQL query sets the password to "admin" for the user "admin", it has to be executed in the ISPConfig mysql database, e.g. with phpmyadmin. If you dont have phpmyadmin installed, then the query can be executed with the mysql commandline utility as well:

Login to the mysql database.

mysql -u root -p

Then enter the password of the mysql root user. To switch to the ISPConfig database, run this command:

use dbispconfig;

And execute the SQL command:

UPDATE sys_user SET passwort = md5('admin') WHERE username = 'admin';

Finally close the mysql shell:


How to open winmail.dat files on Ubuntu and Debian Linux

The winmail.dat file is a container file format used by Microsoft Outlook to send attachments in richtext formatted emails. To open winmail.dat on Linux, use the tnef utility.


sudo apt-get install tnef


Open a shell window, navigate to the directory where the winmail.dat file is saved,  then execute the command:

tnef winmail.dat

to extract all files that are stored in the winmail.dat into the current directory.

How to improve text readability in Windows 7

Windows 7 comes with a handy utility to tune the readability of text. To start cttune, press the keys [Windows] + [R] to open the windows command line. Then enter


and click on "OK" to open the ClearType Text Tuner.


Then follow the steps of the tuning wizard by clicking on next and selecting the text samples that look best on your computer.


How to enable port 465 (smtps) in postfix mailserver

More and more internet access providers are closing port 25 to reduce spam except for connections to their own mailservers. If you run your own mailserver and have problems to connect to it on port 25, you can enable port 465 (smtps) in postfix as a workaround. Edit the /etc/postfix/ file:

vi /etc/postfix/

and remove the # in front of the smtps line. Example for Debain 5, change the line:

#smtps     inet  n       -       -       -       -       smtpd


smtps     inet  n       -       -       -       -       smtpd

and restart postfix:

/etc/init.d/postfix restart

How to delete saved passwords for network drives in Windows

If you saved a password for a network drive in windows and want to remove it, press the keys [Windows] + [R] to open the windows command line. Then enter

control keymgr.dll

and click on "OK" to open the windows credential manager which allows you to manage and delete passwords saved in Windows.


This procedure works for Windows XP, Vista and Windows 7.

How to install Windows 7 on a Netbook without DVD drive

To install Windows 7 on a Netbook without DVD drive, a bootable USB stick with Windows 7 is needed as installation media. The following FAQ describes the steps to create such a USB stick.

1) Create a ISO image of your Windows 7 DVD. If you have already a .iso file e.g. when you downlodaed Windows 7 from the Microsoft online store, then proceed with step 2. Otherwise we create the Iso file now. I will use the small freeware program called LC Iso Creator from Lucersoft.

Download the file that conatains the LC ISO Creator software and unpack it. Then double click on the LCISOCreator application, select your DVD drive that contains the Windows 7 DVD and select a place were the .iso file shall be stored.


2) Now download the "Windows 7 USB/DVD Download Tool" from the microsoft website and install it. This tool will copy the .iso imago on a USB stick and prepares the usb stick as installation media.

Click on "Start" and then on "Windows 7 USB/DVD Download tool" which is listed in the Section "All Programs".


Select the ISO image in the source file box and click on next.


Click on "USB Device".


Select your USB stick in the dropdown list and click on "Begin Copying".

How to prevent a Linux system user from loggin into the system

If a linux system user is able to login on the shell or with SSH depends on its shell setting in /etc/passwd. If you want to prevent that a certain user is able to login, then set the shell either to /bin/false or /sbin/nologin.

Example for Debian and Ubuntu Linux for the user with the username "otheruser":

usermod -s /bin/false otheruser

For Redhat, Fedora or CentOS use /sbin/nologin:

usermod -s /sbin/nologin otheruser

Warning: Do not set the shell for the root user to /bin/false or /sbin/nologin!

How to prevent that a user deletes a file owned by root in its home directory

If the root user stores a file in the home directory of another user or any other directory that is owned by another user, this other user is able to delete the file even if the file is owned by root and has 700 permissions.


root@workstation:/home/otheruser# ls -la
total 8
drwxr-xr-x 2 otheruser otheruser 4096 Oct 23 11:52 .
drwxr-xr-x 3 root      root      4096 Oct 23 11:51 ..
-rwx------ 1 root      root         0 Oct 23 11:52 root_users_file

If I su now to "otheruser", I'am able to delete the file as "otheruser" is the owner of the directory where "root_users_file" is stored:

root@workstation:/home/otheruser# su otheruser
sh-3.2$ rm root_users_file
rm: remove write-protected regular empty file `root_users_file'? y

Now to protect the file from beeing deleted, use the command chattr +i:

chattr +i root_users_file

and then try again to delete the file as "otheruser", the action will be denied:

root@workstation:/home/otheruser# su otheruser
sh-3.2$ rm root_users_file
rm: remove write-protected regular empty file `root_users_file'? y
rm: cannot remove `root_users_file': Operation not permitted

Now even root is not able to delete or edit the file anymore. With the command chattr -i the protection can be removed:

chattr -i root_users_file

How to extend the Windows 7 activation period to up to 120 days

Windows 7 has to be activated within a period of 30 days.  You can use the following command up to 3 times to extend the activation period to up to 120 days. The Command has to be executed as Administrator user on the Windows shell:

Click on "Start" > "All Programs" > "Accessories" and then right click on "Command Prompt" and select "Run as Administrator"

In the command promt window enter the following command and hit return:

slmgr -rearm


This slmgr command works also on the Test versions of Windows 7 that Microsoft offers on their website. It has to be executed before the activation period ended.