DNS

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 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....