SSH-key-based authentication provides a more secure alternative to password-based authentication. In this tutorial we’ll learn how to set up SSH key-based authentication on a Debian 9 installation.
Send email using SSMTP with the command line on a Raspberry Pi. Step-by-Step Illustrated guide to sending emails through the command line in linux
Source: Send Email from Raspberry Pi Command Line (AlgisSalys.com)
The technique shown in this article, which allows you to send email from the command line or a bash script, uses Gmail to send the mail. It should also work on Debian or Ubuntu based systems.
This is an older article but I believe the information is still valid. The technique shown may also work on other Debian-based distributions, such as Linux Mint and the various Ubuntu derivatives.
Ubuntu’s Update Manager keeps your packages at the latest version, but occasionally a new package version may not work properly. You can downgrade an installed package and lock it at a specific version to prevent it from being updated.
Source: How to Downgrade Packages on Ubuntu (HowToGeek)
I downloaded a .deb Debian file. How do I extract deb package without installing it on my Debian or Ubuntu Linux based system? How do I list and extract the contents of a Debian package?
In this tutorial, I will explain how to use Let’s Encrypt to obtain a free SSL certificate and use it with Nginx on Ubuntu or Debian Linux.
Explain how to undo or rollback an apt-get install command on a Debian or Ubuntu or Mint Linux.
Source: Rollback an apt-get upgrade if something goes wrong on Debian / Ubuntu Linux (nixCraft)
So if ipv6 is not supported on your network infrastructure, it might be useful to disable it all together. Why ? It can cause issues like delayed domain lookups, un-necessary attempts to connect to ipv6 addresses causing delay in network connection etc.
Source: How to disable Ipv6 on Ubuntu, Linux Mint, Debian (BinaryTides)
(This is also applicable to a Raspberry Pi running Raspbian, or some other Debian derivative such as RasPBX)
OpenMediaVault is a Debian based special purpose Linux Distribution to build a Network Attached Storage (NAS) System. It provides an easy to use web-based interface, Multilanguage support, Volume Management, Monitoring and a plugin system to extend it with LDAP, Bittorrent, and iSCSI capabilities. This tutorial describes the installation and configuration of OpenMediaVault.
Source: Build your own NAS with OpenMediaVault – Howtoforge
Network Time Protocol (NTP) presents an unique ability for companies to synchronize the clocks of all the systems within the company. Time synchronization is important for many reasons ranging from application time stamps to security to proper log entries. When an organization’s systems all maintain different clock times, it becomes very difficult from a troubleshooting standpoint to determine when and under what conditions a particular event might be occurring.
NTP provides an easy way to ensure that all systems will maintain the correct time which in turn can greatly simplify the burden on administrators/tech support.
Full article here:
How to Install and Configure NTP (Network Time Protocol) Server/Client in Debian Linux(Tecmint)
If you’re managing Debian or Ubuntu servers, probably, you may use dpkg or apt-get commands often. These two commands are used to install, remove, update packages.
In this brief tutorial, let us see how to check if a package is installed or not in DEB based systems.
Full article here:
Linux Basics: How To Check If A Package Is Installed Or Not In Ubuntu (Unixmen)