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Linux on Willem's Blog

Syncing files seamlessly between smartphone and tablet

Using unison to automatically sync between GNU/Linux and the iPhone

Sep. 16, 2020
In order to optimise my workflow, I was looking for a way to seamlessly access the same files on both my computer and smartphone. Read along to find out how I did it.

In order to optimise my workflow, I was looking for a way to seamlessly access the same files on both my computer and smartphone. This is useful to when you want to quickly send files from your computer using your smartphone through various messaging apps and vice versa. Read along to find out how I did it.

Free from the iCloud: Escaping Apple Photos

Using offline photo library management software

Aug. 31, 2020
Recently I freed myself from Apple Photos, using free software to manage my photo library. Read along to find out what software I use and how to make it play nice with your devices.

After encountering the umpteenth ‘magic’ bug while managing my iPhone’s photos, I was done with it. Apple came a long way since it launched iPhoto (the predecessor of iCloud Photos). But for something as valuable as my personal memories, I want to be in full control. Read along to learn how I migrated my photo library away from the iCloud, using free, open source software.

Traffic shaping using iptables and tc

Limiting outbound network bandwidth per client IP-address

Apr. 1, 2020
This month I responded to an automated alert indicating excessive bandwidth usage on a server, requiring me to apply traffic shaping to mitigate the traffic.

Last month I received an automated alert indicating excessive bandwidth usage, usually a sign of trouble. When this happens, you should follow a standard incident procedure, trying to isolate the source of the traffic before shutting it down. The cause of this incident was not what I expected however... requiring a different kind of mitigation than a simple blockade.

Making my own tablet OS

Installing and modifying Debian GNU/Linux on Surface Go

Mar. 9, 2020
I wondered if I could escape Windows by installing Debian GNU/Linux on a Surface Go, read along to find out how to do this!

For some years now I use a tablet as main computer, I like its versatility. But, most tablets come with a locked down operating system, like iPadOS, Windows 10S or Android. As I like things my own (weird) way, I wondered if I could escape these "software jails" by installing a free operating system on a tablet. It's possible, read along to find out how I escaped!

Your own addressbook and calendar cloud

Share contacts, agendas and tasks with CardDAV/CalDAV

Feb. 28, 2020
You can setup a CardDAV/CalDAV server to manage your own contacts, addressbook, agenda and task data and share it between your devices.

If you use different devices and computers to get things done, you might want to synchronise contacts, agendas and tasks. You can use any of the 'big cloud' services for this, like Apple iCloud, Microsoft Office 365 and Google Gmail. But, if you prefer not to share your addressbook and calendar with big American companies, you can do it yourself.

Building a professional 72TB NAS

Configuration and installation of an HPE ProLiant DL380 server

Nov. 22, 2019
This month I installed a professional HPE ProLiant DL380p server in a datacenter in Amsterdam, read this post to see how this was done!

Over the past few years I have been moving my data and work from local computers (mostly laptops) into the cloud. Cloud computing is done by servers in a datacenter, powerful computers that do the hard work. As my company grew, I needed more capacity. It was time to add some power to my cloud!

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!

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?

Rescuing files from a broken harddisk

Make backups to be safe rather than sorry!

Oct. 16, 2018
Yesterday I helped a young woman with her broken computer containing precious photos, could I safe them?

Yesterday a young woman brought me her laptop, it didn't start anymore and it only showed an error message. It turned out to be a broken harddisk. It startled her when I told her that all data on the disk was lost. She told me it contained precious photos of her pregnancy and young child. What could I do?

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.

Helping people with free software

Installing Debian GNU/Linux on an old laptop

July 20, 2018
This week I helped a man with repairing and reinstalling his computer with Debian GNU/Linux.

This week a man brought his laptop to the community centre where I help people with computer problems as volunteer. The old laptop wouldn't start anymore and had to be reinstalled. Instead of Windows, I installed a free operating system. I think it is important to tell you how and why I did it.

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.

Lessons from a takeaway plastic bag

My ever increasing antipathy to planned obsolescence

Jan. 8, 2018
How we're tricked into repeated purchases replacing perfectly fine products just for the sake of change.

About five months ago I got some take away food from our local Asian restaurant. They packaged the food and gave me a plastic bag to carry it home. On my way home I was thinking about the bag. Although it has some nice styling printed on it, it's designed for single use only. What a waste... making me wonder: how long would it last if you would use it on a daily basis?

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.

Programming on Apple Watch

Serious about crazy experiments

Feb. 16, 2017
Programming with VIM over SSH on Apple Watch using a bluetooth keyboard

Over the past years I have been no stranger to crazy experiments, but this time I really wanted to push it into the extreme: programming on an Apple Watch. Would it be possible to actually write code on such a tiny device? Why even bother? This post is about the case for crazy experiments, and why you should try too!

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
Note the many firmware updates, you can only install them from Windows
Note the many firmware updates, you can only install them from Windows
Plastic bag at work, with food inside protecting the contents of my commuting backpack
Plastic bag at work, with food inside protecting the contents of my commuting backpack
The iPhone 4 replaced my camera in 2010 - selfie of Mr. Blurry Cam
The iPhone 4 replaced my camera in 2010 - selfie of Mr. Blurry Cam
Using nmap to scan a hosting server, identifying network facing services and open ports
Using nmap to scan a hosting server, identifying network facing services and open ports
The Apple Watch is a tiny wearable computer
The Apple Watch is a tiny wearable computer
Surface Pro, type cover and pen - al sold seperately - because, why just one package if you can have three times as much fun!?
Surface Pro, type cover and pen - al sold seperately - because, why just one package if you can have three times as much fun!?
Maybe... my next office? ;-)
Maybe... my next office? ;-)
Apple Watch showing an estimated delivery time of a parcel (from the Dutch PostNL service)
Apple Watch showing an estimated delivery time of a parcel (from the Dutch PostNL service)
Using the customised operating system on tablet to create content for this blog
Using the customised operating system on tablet to create content for this blog
Keep in mind that help is available - I know my way around servers and cyber security
Keep in mind that help is available - I know my way around servers and cyber security
Yesteryear’s memory cards - note that they are sized in MB, as in mega, not gigabyte!
Yesteryear’s memory cards - note that they are sized in MB, as in mega, not gigabyte!
Check for updates manually using Windows Update
Check for updates manually using Windows Update
The Domain Name System (DNS) links domain names to IP-addresses, which in turn are routed through cables. You're reading this - seriously! - through the cable connected to the server shown on this photo!
The Domain Name System (DNS) links domain names to IP-addresses, which in turn are routed through cables. You're reading this - seriously! - through the cable connected to the server shown on this photo!
Nokia 9300i, officially not a communicator but nonetheless a device with advanced mobile communication options for its day (2007). Running Putty on Symbian Series 80.
Nokia 9300i, officially not a communicator but nonetheless a device with advanced mobile communication options for its day (2007). Running Putty on Symbian Series 80.
MacBook acting as monitor and keyboard of the server
MacBook acting as monitor and keyboard of the server
Pen input works using my custom linux kernel and the Xournal app
Pen input works using my custom linux kernel and the Xournal app
Charging and listening to music simultaniously using an Apple Lightning dock
Charging and listening to music simultaniously using an Apple Lightning dock
Implementing stringent SMTP restrictions in Postfix - annotated screenshot from main.cf
Implementing stringent SMTP restrictions in Postfix - annotated screenshot from main.cf

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