Ubuntu

Introduction During the last few years, I have started several blogs (not much success, it must be said). A technology one, my photography web, and a blog with personal matters, which I decided to close. All of them were made with the same CMS platform: WordPress. WordPress has some advantages, such as its ease of use or the great community behind it. However, I was tired of the huge amount of resources I needed to deploy the CMS and give a good experience to the readers of my blog....

Introduction After installing a new Ubuntu system, I always set the language configuration to fit my local environment. Locales configuration Connect to a terminal of your machine and execute next command: sudo dpkg-reconfigure locales After this, you will see a list of languages and countries. You have to select with space bar the language and country you need. In my case, as I live in Spain, I have selected es_ES.UTF-8. It is recommended to choose UTF-8 version....

Grafana is an open source metric analytics & visualization tool which can help us to monitor the system with a nice Dashboard. Installing Grafana Grafana is available in the APT packages repository, however it could not be the latest version, so we’ll use the official Grafana repository. First, it is needed to install the software needed before install Grafana. sudo apt install -y apt-transport-https sudo apt install -y software-properties-common wget Next step is to download the GPG Key, in order to install signed packages:...

Introduction Some time ago I tried to configure a SMTP server in a host in the cloud, but because of some restrictions, the emails from that server were bounced. The problem was that the hosting provider didn’t configure the PTR DNS entries (more about DNS PTR entries) for some kind of hostings. When this happens the best solution is to use a SMTP relay server, by this way that server is in charge of the final delivery of the emails....

Introduction Nowadays, the knowledge to install a mail server is an important task for any System Administrator. In our case, we are going to see how to deploy a mail server with Postfix on Ubuntu. About Postfix Postfix is a free and open-source MTA (Mail Transfer Agent) which routes and delivers electronic mail (e-mails). As an SMTP server, Postfix implements a first layer of defense against spambots and malware. Can be used to send and receive e-mail....

In my diary activities usually I have to check the connectivity between two hosts. In this article I will explain which is the method I use to do it. ...

iPerf is a tool designed to test the bandwidth between two hosts using the network. It is a really simple, powerful CLI which allows generating traffic / load TCP or UDP between 2 hosts. You could use to measure the maximum bandwidth of the network between a client and a server. It can be used to do stress tests of the Ethernet, Wi-Fi or of your ISP. iPerf2 vs iPerf3, what is the difference?...

In some situations could be needed to know exactly which DNS server is being used by an Ubuntu host. There are several ways to get this info, however the best option I have found is to use the systemd service systemd-resolve. This service is in charge of the name resolution of the local applications. You can use it executing systemd-resolve --status or just resolvectl. The command will return the DNS servers configured in each network interface, and which one is currently being used....