Using self-signed certificates, without a certificate authority, "x509: certificate signed by unknown authority" errors are raised when using command lines for very specific needs (curl…). For self-signed certificates, it is quite possible to create its own tiny certificate authority (CA) in order to avoid using options which prevent the SSL complete chain check up to the certificate authority (curl --insecure, influx --skip-verify…).

In most programming languages, it is convenient to use locale settings for displaying numbers, dates… Locale settings avoid developing functions to format data. The major inconvenient : locale settings are OS dependent. If a requested locale is not installed on the OS where the program runs, formatting will fail or will fallback to default settings. A quick overview about locale settings on Ubuntu : installation, temporary or permanent modification.

On Ubuntu servers, ufw (Uncomplicated Firewall) is a good tool to apply firewall rules on ports without having to use iptables commands which are quite difficult, but it's not enough to protect port 22 for SSH services. Fail2Ban is the complementary tool to ufw in order to protect an Ubuntu system from attacks on SSH. Fail2Ban is a Python package which interacts like ufw with iptables and can be installed in a Python virtual environment, this is the case in this article.

The first three steps to secure a new Ubuntu server, server located in the cloud or not :

• Change the default port for SSH connections.
• Disable direct SSH access using the root account.
• Enable ufw (Ubuntu Uncomplicated Firewall) by allowing incoming SSH connections.

In a context where SSH is running on a different port than the default one, how do you safely enable ufw for the first time by allowing SSH connections? In many articles, the reader is warned to be careful when activating ufw but without pointing out the ufw show added command. This command ensures that there is no human error before activating ufw, human error that can cut existing SSH connections without the ability to establish new ones other than by soliciting the provider (cloud) or by physically accessing the server.

For writing code, vim is an excellent tool on Linux systems, but when you are used to the Active State Komodo Edit tool on Windows platforms, in particular for its project definition features, workspaces… you may want to run Komodo Edit on Ubuntu and transfer the GUI on its Windows 10 client. Active State Komodo Edit can be installed and run on an Ubuntu system and the GUI transferred to a Windows 10 client using "X11 forwarding". The prerequisites and installation are fairly straightforward.

When graphical desktops are not installed on an Ubuntu server, sometimes graphical interfaces are required and must be transmitted and displayed on client machines. As examples :

• Complex installation programs (Oracle…), the graphical version is often preferred to the console mode and/or silent installations.
• Running Android studio on an Ubuntu server, more powerful, rather than on the client machine which does not meet the hardware prerequisites (memory, CPU, etc.).

Very few steps on Ubuntu 18.04 and Windows 10 client to implement this mechanism.

Fiche technique exposant les opérations préalables pour l'installation de Sybase Replication Server v 12.0 avec Sybase Adaptive Server Enterprise v 12.5 sous Linux

Guide rapide de la compilation et de l'installation d'Apache 1.3.23 sous Linux

Guide rapide de la compilation et de l'installation de MySQL 3.23.49 sous Linux

Fiche technique sur la compilation de Php v 4.2.0 sous Linux avec intégration des fonctionnalités de Sybase Adaptive Server Enterprise v 12.5 et sur l'installation de PhpMyAdmin 2.2.3

Services sous Linux : niveaux de démarrage, arrêt, statut… Cas concrets avec les services Apache et MySQL.