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Cloud on Willem's Blog

Fighting backscatter spam at server level

Configure Postfix to block spam before it enters the server

Sep. 10, 2019
Deal with backscatter spam by implementing a stringent SMTP delivery policy at MTA level.

This month I had to deal with backscatter spam, affecting one of the mail servers I manage. As server engineer I make sure that servers don't send spam and that incoming email gets filtered. Despite all good efforts, this server kept being blacklisted for sending spam to iCloud, Office 365 and Google Gmail for Business (G Suite). Read along to find out how what caused this and how to fix this.

Dig for dummies

Explaining an highly useful network tool

May 24, 2019
Learn how to use the dig command to query domain name servers to find the source of network problems, IP-addresses, hostnames, mail servers and related info.

When you're building websites, apps or email services you may run into domain names and their configurations. When everything is working as it should, most of this is invisible. But when troubleshooting a domain name configuration, it may be necessary to dig a little deeper... read along to learn how!

Search like a pro: Google search operators

Comprehensive list of advanced search operators

Apr. 25, 2019
Read along for a comprehensive list of advanced Google search operators that allow you to filter your search results.

You probably use the world's most famous search engine to find things everyday, but you might not know about some of its advanced search operators. You can use these special search phrases to find things that are otherwise burried in the search results. Read along for a comprehensive list of advanced Google search operators.

WordPress: 10 tips to secure your website

Keep hackers out of the world's most popular content management system

Mar. 31, 2019
A lot of people use WordPress to manage their website. Prevent your site from being hacked using this blog post.

A lot of people use WordPress to manage their website, therefore it's no surprise people ask me to have a look at their site's security. As ethical hacker, I encounter WordPress in different shapes, sizes and states. Some of them are really badly protected against hacks. Prevent your site from being hacked using these 10 practical tips.

Understanding the security concerns in shared hosting

Considering open ports and unused network facing services

Feb. 28, 2019
People pay me to hack them, provided I'll explain how I did it. Read along to learn how hackers use security holes to hack your app, webshop or website!

People pay me to hack them, provided I'll explain how it was done, so future hacks can be prevented. As security consultant, I scan for weaknesses in my clients' apps, webshops and websites. Very often a hack starts by exploiting a security hole that is visible remotely. Read along to learn how hackers find security holes and what you can do to secure them.

Is the Apple Watch the modern tool watch?

Testing the Apple Watch's usefulness in real life

Nov. 2, 2018
I tested the Apple Watch during my work in Frankfurt this week where I had to go inside an internet data centre.

This week I went to Frankfurt for business. I had to perform maintenance to servers in a data centre. This seemed like a great opportunity to test the Apple Watch's usefulness in real life (other than health and fitness). I wondered, is the Apple Watch the modern tool watch?

Optimising images for the web and performance

Reduce filesize with jpegoptim, optipng, pngcrush and pngquant

Sep. 26, 2018
Make your website faster by optimising the images. This posts explains how you can do this.

One way to make your website faster is to make it smaller. Not with tiny fonts, but with less bytes! More than half the weight of an average website is because of images. Yet very few people optimise their images for the web and performance, time to find out how much bytes you can safe!

Google Analytics vs AWStats

Understanding web traffic statistics software

Aug. 20, 2018
Comparing Google Analytics with AWStats to find out where they differ and which is better.

This month I have been working on website statistics, tracking traffic using different technologies. Some of my customers use Google Analytics, others use AWStats, and some use both. Which is better is often debated, but few people really understand the differences. Time to shed some light on the magic of web statistics.

Cyber security: 5 easy tips to protect your server against hackers

Server hardening best practices for Windows and Linux

Mar. 10, 2018
These 5 practical cyber security measures will improve the safety of server, website and data.

This week one of my clients was hacked and asked me for emergency assistance to help secure their server infrastructure. It was a web server that ran WordPress websites on Apache (with PHP/MySQL), including a few webshops with customer data. This hack could easily have been prevented with the following best practices, is your server secure?

Tablet as main computer

Comparing the Microsoft Surface Pro to iPad Pro

Mar. 7, 2018
I have been using a tablet as my main computer for quite some time now. In this blog post I share you my experience on using Surface Pro and iPad Pro to get my work done.

For the past few weeks I have been using the Microsoft Surface Pro as my main computer. It's a modern tablet computer that can be used as laptop with the type cover. With the Surface Pen, it's a versatile PC that works in a lot of different ways. Time to find out if it's any good and how it compares to my other tablet computer, iPad Pro.

Clouds below my floor

Building a little datacenter in my basement

Aug. 31, 2017
Building a little datacenter in my basement utilising a very fast internet connection.

At my home I have this crazy fast optical internet connection. It is a 600MB up and down fibre connection which directly arrives in my home (no copper cables involved). It's like a private internet highway. Reason enough to find out if I could do something to make better use of all this speedy fiber galore...

The day I killed my LAN

Turned off my local network and went 4G only

July 31, 2017
I killed my office LAN and went 4G only. Saves a lot of clutter, energy and money.

Today I called my provider to quit my office's ADSL internet subscription, I don't need it anymore. I have turned off my local area network and switched my workflow onto mobile internet only. The simplicity and savings actually surprised me so much, that I made blog post for it.

iPad Pro next to my primary machine

Using it with Apple Pencil as a creative powerhouse

Jan. 30, 2017
Using iPad Pro with Apple Pencil next to my computer to form a create powerhouse

I wanted see if I can find something better than my old fashioned pencil and paper that I use for designing software as professional developer. I knew iPad Pro from my test last summer, figuring out if it could replace my primary development machine. While it may not be able to completely replace my thrustworthy ThinkPad, it turned out to be a totally different story when it comes to paper.

iPad Pro as primary computer

testing iOS as primairy development platform

Aug. 15, 2016
Is the time right to use an iPad as primary development platform to get some real work done?

The lack of physical clutter, distracting branding, or blinking LED's makes the iPad Pro a textbook example of minimal design. My despiction of distraction explains my interest in using the iPad Pro as only computer to test if it is up to the task. Is Apple's latest effort on iOS enough to enable it to do serious development work?

Building the blog... in style!

Developing on a 20-year old computer with 16MB RAM and Windows 98

June 23, 2016
Find out if it is possible to turn a computer from the 90s into a modern development machine.

One must be a bit crazy to come up with the idea to build a blog (as in: actual programming) on an old 486 laptop with just 16MB RAM. I happen to be that crazy: I took my very first laptop from the 90s and decided to find out if it was possible to turn it into a development machine.

All blog posts
Somewhere in a datacenter there is a machine like this hosting your website
Somewhere in a datacenter there is a machine like this hosting your website
Programming on iPad Pro using VIM, Blink and a Linux VPS
Programming on iPad Pro using VIM, Blink and a Linux VPS
The iPad Pro works well with a normal bluetooth keyboard
The iPad Pro works well with a normal bluetooth keyboard
Once a hacker knows what software your website uses, its easy to lookup known security holes using databases like cvedetails.com
Once a hacker knows what software your website uses, its easy to lookup known security holes using databases like cvedetails.com
Windows on iPad is possible using Remote Desktop
Windows on iPad is possible using Remote Desktop
Touch screens are important these days when designing (and testing) interfaces
Touch screens are important these days when designing (and testing) interfaces
Apple Watch - a modern tool watch?
Apple Watch - a modern tool watch?
Clouds below my floor: my little basement datacenter.
Clouds below my floor: my little basement datacenter.
Never thought I would be happy to see this: the Windows 98 boot screen!
Never thought I would be happy to see this: the Windows 98 boot screen!
I had to remove the original disk because it didn't work... or so I thought!
I had to remove the original disk because it didn't work... or so I thought!
Do you trust the free wifi you're using? (Image via buffered.com)
Do you trust the free wifi you're using? (Image via buffered.com)
The Apple Watch is a tiny wearable computer
The Apple Watch is a tiny wearable computer
Autodesk Graphic is an amazing app for iOS - I use it to design icons and graphics, with layers and alignment tools
Autodesk Graphic is an amazing app for iOS - I use it to design icons and graphics, with layers and alignment tools
Shiny new Apple iPad Pro, Apple Pencil and the Smart Keyboard
Shiny new Apple iPad Pro, Apple Pencil and the Smart Keyboard
The world on your wrist - using Apple Maps in downtown Frankfurt
The world on your wrist - using Apple Maps in downtown Frankfurt
Working with Surface Pen and Apple Pencil
Working with Surface Pen and Apple Pencil
Sitting on some concrete tiles the modified PC is connected to the internet
Sitting on some concrete tiles the modified PC is connected to the internet
Reading using a tablet computer is not limited to your desk - I like reading on the couch
Reading using a tablet computer is not limited to your desk - I like reading on the couch

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