Welcome to Rob Groen's website

The Internet Jigsaw

Internet and internet systems are like one big jigsaw. Every piece has to be on the right place. If just one piece isn't right than you won't get the result you hoped for.

E-commerce specialist

I am a E-commerce specialist and can help you with many questions about this fantastic way of selling you products or services. In the late '90 I started a web shop for selling white-goods over the Internet on the Dutch marked. I was the first one who did that and there was no software like Drupal of OS-Commerce. I had to invent it all by myself. It was a great time!.
The shop was very successful and some day a big company made me an offer that I couldn't refuse. So I sold my e-commerce business.

Now I use my knowledge to advice and help other e-commerce companies to get better, grow and make more profit. My strength is the combination between technique and commerce.

Linux specialist

I am a Linux specialist and work with Linux since 1997. I am using mainly Debian based distributions like Debian and Ubuntu.
Please let me help you to find the pieces you need and how to stuck them together.Visit my Linux Tips & Trick page to see some helpful solutions.

Scheveningen Luxemburg Scheveningen

Classic SLS Rally

Since 1995 I drive with the technical service and repair group in the Classic SLS Rally. this Rally is for old car dated before 1975 and they drive from Scheveningen, a famous city on the west coast from The Netherlands, to downtown Luxembourg city and back again.

The rally includes 2 nightly stays in Belgium.

SLS Rally Medaille

Portfolio overview

A overview with some of my website projects. I prefer building websites in Drupal, Joomla and OS-Commerce.

Legal Account


A website for a Legal Office in Holland.
Build on the Joomla platform. Sending newsletters and has a restricted area for members to meet other enterpricers in the same business.




Geldverspilling is Dutch for waisting money. It's a website about money waisting project from the Dutch government.


Red White Blue Shop


The Red White Blue Shop is a webshop for selling solar panels on the USA market. The shop is build on the Drupal platform extended with Ubercart webshop module.

The customer can pay with all kind of credit cards and the USP shipping coast are calculated depending on weight and distance.


Kinderboerderij Alphen a/d Rijn


When the child farm in my village needed a new website I offered to take that job and made a brand new website for free.

The site is made in Drupal with some extra modules. Most of the functions are from the Drupal core. I made a special place for the volunteers, the press and a forum & Blog for each member.



Screenshot Internetshop

Internetshop.nl is my primary website for selling white goods to consumers using the internet. I got the idea for selling those products in 1998 and started building a static website in plain HTML. Later a dynamic website, build in Perl in combination with a Postgresql database, replaced the HTML version.

Latest Tips & Tricks

My latests solutions for Linux software problems.
(English Only)

How-To Resize mailbox size in Zpanel on Ubuntn 12.04

Running a Zpanel on a Linux server and you want to resize the users mailboxes? This is how to do that.

The standard size of mailboxes in Zpanel is 200Mb

You can change the size of new mailboxes in:
Admin -> module admin -> Mail Config -> Max Mailbox Size
Remember that only new created mailboxes will have this size!

Create test files of specific size

Sometimes you need file of an exact site for testing purpose like an email attachment.

Here is how you make them in Linux command line:

dd if=/dev/zero of=file_5Mb.txt bs=1k count=5120
dd if=/dev/zero of=file_7Mb.txt bs=1k count=7168
dd if=/dev/zero of=file_8Mb.txt bs=1k count=8192
dd if=/dev/zero of=file_8.8Mb.txt bs=1k count=9011

Create test files of specific size

dd if=/dev/zero of=file_5Mb.txt bs=1k count=5120
dd if=/dev/zero of=file_7Mb.txt bs=1k count=7168
dd if=/dev/zero of=file_8Mb.txt bs=1k count=8192
dd if=/dev/zero of=file_8.8Mb.txt bs=1k count=9011
dd if=/dev/zero of=file_9Mb.txt bs=1k count=9216

ls ./file_* -lah
-rw-r--r-- 1 rob disk 5,0M feb 20 14:30 ./Desktop/file_5Mb.txt

How-to Install Spamassassin and Postgray on Ubuntnu 12.04 Zpanel 10.10

Here is a script to install Spamassassin and Postgray on Ubuntnu 12.04 Zpanel 10.10


# #
# Version 1.1 #
# #

How-To Copy all in- and outgoing email of a certain domein with Postfix and Z-Panel

This instructions tells you how to make a copy of in- and outgoing emails from a certain domain server running Postfix and Z-Panel.


There are multiple domains on a (Z-Panel)server running multiple websites and email from different customer. One customer wants a copy of in- and outgoing email for 3 domains sent to a special email address.


Fotografie is al sinds mijn jeugd een hobby. In de jaren '70 fotografeerde ik met een 2-hands grootbeeld spiegelreflex camera. Echt een oudje en ondanks zijn leeftijd een prima camera. Dat was in die tijd normaal dat je naast je camera ook een aparte, losse belichtingsmeter bij je had. Immers met de camera kon je niets ander dan scherpstellen, de sluitertijd en het diafragma instellen.