.NET Core – gdiplus.dll not found in Linux

A few days ago there was an issue raised in my QrCoder project. It was reported that the code would not run under Linux, as the following error message would occur:

Unhandled Exception: System.TypeInitializationException: The type initializer for ‘System.Drawing.KnownColors’ threw an exception.
—> System.TypeInitializationException: The type initializer for ‘System.Drawing.GDIPlus’ threw an exception.
—> System.DllNotFoundException: Unable to load DLL ‘gdiplus.dll’: The specified module could not be found.
(Exception from HRESULT: 0x8007007E)
at System.Drawing.GDIPlus.GdiplusStartup(UInt64& token, GdiplusStartupInput& input,

However the error message had its origin not in my QrCoder, but in the interplay of the .NET core framework with the GDI Plus library. The .NET Core Framework tries to access “gdiplus.dll” when accessing “System.Drawing.GDIPlus”, which is simply not available on Linux.
First solution approach
First, ensure that GDI+ is installed at all. This can be done with the following shell command:

sudo apt-get install libgdiplus

If libgdiplus is installed, however, another important step is missing …
Link libgdiplus for .NET Core
Because the […]

How to fix SSL error 61 in Citrix Web Receiver on Linux

How to fix SSL error 61 in Citrix on LinuxI admit, the title is quite specific and will certainly appeal to only a small readership. But anyone who is facing the problem will be, like me, grateful for a solution.
In particular, the problem is about the SSL error 61 in the Citrix (Web) receiver under Linux and how to fix it. Since I have been running almost exclusively under Kubuntu for several months, the Citrix Reiceiver also moved into the new Linux box. Unfortunately, no connection to systems could be established, since the receiver disconnected with the following error message.
SSL Error 61: You have not chosen to trust “Go Daddy Root Certificate Authority – G2”, the issuer to the server’s security certificate.
Citrix-SSL-Fehler-61What […]

How to read, calculate and set MTU in Windows, Linux and OSX

After I released the MTU Optimizer, a small tool for determining the optimal MTU, some days ago, let’s look at how to determine the optimal MTU by hand, how to read the currently set MTU and how to set new MTU value now. Of course we will discuss the whole thing for the three major operating systems: Windows, OSX and Linux.
Before we look at the implementation within the individual operating systems, we first briefly clarify what the MTU is and how its optimal value can be calculated.
Theory – Identify ideal MTU
The MTU (Maximum Transfer Unit) describes the maximum packet size of a protocol. It therefore indicates the maximum size of a data packet, so that it can be transmitted via a protocol. If a data packet is larger, it becomes fragmented – i.e. divided into several packages.
For example, let’s assume that we (=PC) would have a factory for sugar packets and our packet […]

How to install Netis WF2190 driver under Kubuntu

How to install Netis WF2190 in KubuntuThe following article is about how to find and install the appropriate (K)ubuntu driver for the Netis WF2190 WLAN stick. For a few weeks I work mainly under Linux (again) and as with almost every of my attempts trying to switch from Windows to Linux, there were again difficulties with the WiFi this time.
So, to spare you the hassle, I wrote the following short tutorial for you about how to install the Netis WF2190 drivers under Kubuntu.
Finding a Linux driver for a Netis WiFi stick
Before we begin, let’s make a small test by lsusb command. If you enter this command in the terminal, all connected USB devices are listed with fuirther information.


As shown in the screenshot below, our WiFi stick is also included in […]

How to convert Audible aax files to mp3 in Linux

Convert Audible aax-files to mp3 in LinuxSo far I always assumed that when I buy music or audiobooks on Amazon for download, I’ll get mp3 files for download. Far from it – yesterday I once again bought a an audiobook and had to find out that I was forwarded after the purchase to Audible and there was confronted with a “protected” aax file. If I wanted to buy at Audible, I would have gone to Audible. Thanks for nothing, Amazon!
But now the following question arises: “How do I convert the proprietary aax files into mp3’s, which I can play everywhere?” (aax files are only playable with the official Audible apps which aren’t available on all platforms.) After all, when buying on Amazon, there wasn’t the talk about the fact that the purchased audiobook can […]