Ubuntu

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....

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?...

Some people are interested in have a private server in order to play CS GO (Counter-Strike: Global Offensive) with their friends. The process is easy to follow. What is needed? A server Memory: At least 2GB RAM (I recommend 4GB) Disk: At least 15 GB os disk space CPU architecture: x86 (ARM not supported) A Valve account Create a new user First of all, it is important to create a new user in Linux in order to prevent CS GO server possible hacking to affect your Linux node....

Using a Linux Operating System, there is a high level of customization, depending on your preferences or needs. One important thing is to create aliases to the most common commands in order to optimize the time you use. In mi case, I love to use .. instead of cd .. or update to update all my Linux software pending updates. Here I put my list of aliases for Ubuntu (based on Debian) or CentOS (based on RHEL) distribution....

By default, Ubuntu desktop installation will provide DNS resolving configured, however in Ubuntu server installation avahi-daemon (or mdnsresponder) is needed to be installed to provide local LAN DNS resolution. In my case, i found the error “Temporary failure in name resolution” when I tried to resolve a machine of my LAN from Ubuntu. yvoictra@zoar:~$ ping erie.local ping: erie.local: Temporary failure in name resolution To solve this issue, there is no need to install a DNS server in the LAN....

The sudo command allows users to run programs with the security privileges of another user, by default, the root user. First if all, the user should be created in the system if it doesn’t exists yet. On Ubuntu systems, by default members of the group sudo are granted to sudo command access. Once the user is created, from root user, or a user with sudo access, you have to execute this command to add the user to sudo group....

Monitoring network traffic or bandwitdh usage is a must in a SysAdmin tasks. There are many differents tools to manage this monitoring, but one of my favorites is vnStat. The main advantage of this tool is the simplicity of its usage. Installation With Ubuntu, the way to install this tool is with apt. sudo apt install vnstat First steps Once installed, it is important to know which interfaces are going to be monitoried....