Free SSL Certificate / Zertifikat

Let’s Encrypt
Let’s Encrypt Glossar

ZeroSSL – FREE SSL Certificate Wizard

Wie Sie ein Let’s Encrypt Zertifikat erstellen und in ein Webhosting-Produkt einbinden
Certbot: Let’s Encrypt TLS-Zertifikate für Mailserver (Deprecated!)

Multiple SSL Certificates with One IP Address

Server Name Indication (SNI)
Using Multiple SSL Certificates in Apache with One IP Address
Apache SNI Browser Support
Multi-Domain (SAN) Certificates – Using Subject Alternative Names
Was ist Server Name Indication (SNI)?
SSL vs. TLS – Worin bestehen die Unterschiede?
SNI (Server Name Indication)


pfctl cheat sheet

FreeBSD 12 & BIND 914

FreeBSD: Install an authoritative DNS server (BIND) (with DNSSEC)

Test / Analyzer

MX Toolbox – SuperTool
DNS Checker
Verisign Labs – DNSSEC Analyzer

$ ls /usr/local/etc/namedb
namedb -> /var/named/etc/namedb

$ ls -la /var/named

$ ls -la /var/named/etc/namedb

$ cat /etc/fstab
# Device        Mountpoint      FStype    Options           Dump    Pass#
/dev/ada0p2     /               ufs       rw                1       1
/dev/ada0p3     none            swap      sw                0       0
/dev/ada0p4     /var            ufs       rw                2       2
/dev/ada0p5     /tmp            ufs       rw                2       2
/dev/ada0p6     /usr            ufs       rw                2       2
fdesc           /dev/fd         fdescfs   rw                0       0
devfs           /var/named/dev  devfs     rw,ruleset=4      0       0
$ /usr/local/sbin/named -fg -t /var/named -u bind -c /usr/local/etc/namedb/named.conf

Qt: Qt/C++ – Tutorial

Qt/C++ – Lesson 004. QSqlTableModel – How to present the table from database?
Qt/C++ – Lesson 008. QDataWidgetMapper – Working with the database via a widget
Qt/C++ – Lesson 019. How to paint triangle in Qt5. Positioning shapes in QGraphicsScene
Qt/C++ – Lesson 021. The drawing mouse in Qt
Qt/C++ – Lesson 027. Polymorphism in Qt by the example of geometric shapes in QGraphicsScene
Qt/C++ – Lesson 036. QWebView – How to make simple browser on the Qt
Qt/C++ – Lesson 045. SvgReader on the Qt. Loading data from SVG file into QGraphicsScene
Qt/C++ – Lesson 050. Logging Qt application events to a text file
Qt/C++ – Lesson 054. Reading data from a CSV file, and their representation via QStandardItemModel
Qt/C++ – Lesson 056. Connecting the Boost library in Qt for MinGW and MSVC compilers
Qt/C++ – Tutorial 063. Adding windows inside the main application window using QMdiArea
Qt/C++ – Tutorial 067. Using QMultiMap for a dictionary of synonyms
Qt/C++ – Tutorial 068. Hello World using the CMAKE build system in CLion
Qt/C++ – Tutorial 069. XOR Encryption
Qt/C++ – Tutorial 070. Crop image using QGraphicsScene
Qt/C++ – Tutorial 072. An example of a vector editor on Qt
Qt/C++ – Tutorial 073. Signals and slots. Connecting Slots to Overloaded Signals in the Qt5 Syntax
Qt/C++ – Tutorial 075. Improving the syntax of signals and slots in Qt 5.7 and above for overloaded signals and slots
Qt/C++ – Tutorial 076. Visualizing Mathematical Formulas on Qt
Qt/C++ – Tutorial 078. Do not mix the old syntax of signals and slots on SIGNAL SLOT macros with new syntax on pointers
Qt/C++ – Tutorial 079. foreach vs range-based for in C++11?
Qt/C++ – Tutorial 081. How to make a base class for widgets using ui form files
Qt/C++ – Tutorial 082. Custom widgets in the Qt Designer
Qt/C++ – Tutorial 083. Creating a dynamic library and connecting it to another project
Qt/C++ – Tutorial 084. How to run JavaScript code in a C ++ application using the example of working with two variables
Qt/C++ – Tutorial 086. Using QSequentialAnimationGroup and QPropertyAnimation to move a button
Qt/C++ – Tutorial 087. Get the maximum number of multiple input fields QLineEdit
Qt/C++ – Tutorial 088. Text search with highlighting in QTextEdit


Qt WinAPI – Lesson 009. SetWindowsHookEx – Logging mouse events via WinAPI

LaTeX: Custom Titles / Sections


Nice customised titlepage for every section (scrartcl)



Incompatibilities between KOMA-Script and titlesec


The titlesec and titletoc Packages (PDF)
Spacing before and after section titles




Windows 10 Bluetooth SPP – Two Virtual COM Ports


Bluetooth Serial Port settings for Windows10 PC
It is true that with Windows own Bluetooth software two virtual COM ports are created after pairing:

  • when connecting your terminal program to the first you are actually instructing Windows to attempt to establish the Bluetooth connection to the remote paired device, and if the connection is established the RFCOMM channel will be opened for the exchange of data
  • when connecting your terminal program to the second you are actually instructing Windows to load the SPP SDP record and to remain waiting for incoming connections from the remote paired device.


difference between incomming BT com-port and outgoing?

  • An incoming port is used when a remote device established a connection to your device, and is exposed as the SerialPort service to the remote device.
  • An outgoing port is used to make a connection to the serial port service on a remote device (e.g. GPS Receiver).


*TWO* virtual serial ports created on Windows (BT121 class SPP)

How to find Bluetooth settings in Windows 10
Virtual Bluetooth adapter settings on windows 10