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.

lsusb

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 […]

How to disable PHP OPCache for certain directories

Deactivate OPCache per folderIn this article, I want to show you how to disable the OPCache based caching for certain directories. (If you need a short introduction to the subject of OPCache, you should scroll down to the blue box in this article.) Although OPCache is a good idea in almost all cases, there are, as with many thing, situations where you should make an exception. Especially when it comes to the development or if a bugfix is to be tested, it can make sense to disable OPCache.
However, since other projects that benefit from OPCache are often running on the same web server, a complete deactivation of OPCache for such test cases can not be an option. Therefore, this article is about how to disable OPCache on the directory level.
In […]

Switch WordPress to HTTPS with free Let’s Encrypt certificates

How to switch your WordPress blog to HTTPSAs the one or other may have noticed, en.code-bude.net is running strictly via HTTPS protocol since some days. All requests via HTTP protocol will be redirected to HTTPS. How exactly the switch from HTTP to HTTPS for code-bude.net was realised and what things to have in mind, I want to explain in the following article.
This article shall show you how to change your WordPress blog setup from HTTP to HTTPS. As a basis for the article I used my setup, which consists of a VPS (virtual private server) with runs Ubuntu Server as operating system and Apache as a web server.
To give you a better overview, I divided the article in the following parts:

Why you should use HTTPS for a WordPress blog?
How to install Certbot and generate SSL certificates
Automatically renew SSL certificates with Certbot
Configure Apache to use Let’s Encrypt certificates
Switch […]