Whether you want to access the Internet safely and securely while connected on an untrusty public Wi-Fi network, bypass Geo-restricted content or allow your coworkers to connect securely to your company network when working remotely, using a VPN is the best solution.

A VPN allows you to connect to remote VPN servers, making your connection encrypted and secure and surf the web anonymously by keeping your traffic data private.

There are many commercial VPN providers you can choose from, but you can never be truly sure that the provider is not logging your activity. The safest option is to set up your own VPN server.

This tutorial will explain how to install and configure OpenVPN on Debian 9. We will also show you how to generate clients certificates and create configuration files

OpenVPN is a fully featured, open-source Secure Socket Layer (SSL) VPN solution. It implements OSI layer 2 or 3 secure network extension using the SSL/TLS protocol. weiterlesen

Asterisk is the most popular and widely adopted open-source framework for building communications applications. It is used by individuals, small businesses, large enterprises and governments worldwide.

Asterisk features include conference calling, voicemail, music on hold, call transfer, call queuing, call recording, database store/retrieve and much more.

In this tutorial we will show you how to install Asterisk 15 on Debian 9.

An older version of Asterisk (version 13) is available in the Debian software repository and can be installed with apt install asterisk.


1. Overview

The term socket programming refers to writing programs that execute across multiple computers in which the devices are all connected to each other using a network.

There are two communication protocols that one can use for socket programming: User Datagram Protocol (UDP) and Transfer Control Protocol (TCP).

The main difference between the two is that UDP is connectionless, meaning there is no session between the client and the server while TCP is connection-oriented, meaning an exclusive connection must first be established between client and server for communication to take place.

This tutorial presents an introduction to sockets programming over TCP/IP networks and demonstrates how to write client/server applications in Java. UDP is not a mainstream protocol and as such may not be often encountered.


Learn how to use BIND to set up your own server for resolving domain names.

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In this article, I show you how to build your own name server using BIND (Berkeley Internet Name Domain). It is not as difficult as you might think, especially because you can do it in two stages.

In this article, you will start by learning how to create a caching name server, then you will move on and learn how to upgrade that to a complete primary (master) domain name server for your network, complete with forward and reverse zone files.


Eigentlich ist das Port-Forwarding im Router so eingestellt, dass der Remote Zugriff auf den Heimserver problemlos funktioniert. Leider hat der Provider aber die Möglichkeit den Router neu zu initialisieren (und damit meine Forward-Regeln zu löschen) und er macht auch massiv Gebrauch davon. Zwar kann der Server dann weiterhin mit dem Internet kommunizieren (und so auch als nagios-Server andere Server überwachen), der Zugriff von außen funktioniert aber nicht mehr.