KVM (Kernel-based Virtual Machine) is an open-source virtualization technology that allows you to run multiple virtual machines on a single physical server. Here’s how you can install KVM on an Ubuntu 20.04 LTS headless server: First, update the package repository by running the command “sudo apt update” Next, install the KVM package and other required … Read more

In Ubuntu 20.04, you can add a network bridge (br0) using the nmcli command-line tool. Here are the steps you can follow: Start by making sure that the network-manager package is installed by running the following command: sudo apt-get install network-manager Next, you can create a new bridge by running the following command: nmcli connection … Read more

Wireguard is a modern, secure VPN protocol that can be used to set up a virtual private network (VPN) on a FreeBSD jail. Here’s how you can install the Wireguard VPN client in a FreeBSD jail: First, create a new jail using the command “jail -c -n jail_name” Next, enter the jail using the command … Read more

In Squid, you can test the configuration file for syntax errors by using the squid -k parse command. Here are the steps you can follow: Open a terminal window and navigate to the directory where the Squid configuration file is located. Run the following command to test the configuration file for syntax errors: squid -k … Read more

In Ubuntu and Debian Linux, you can use the apt-mark command to hold back packages from being upgraded. Here are the steps you can follow: Start by updating the package list by running the following command: sudo apt-get update Next, you can hold back a package by running the following command: sudo apt-mark hold package_name … Read more

Amazon Route 53 is a DNS service offered by Amazon Web Services (AWS) and acme.sh is a command-line utility for automating the process of obtaining and renewing Let’s Encrypt SSL/TLS certificates. Here’s how you can use acme.sh to obtain a wildcard certificate for a domain hosted on Route 53: First, install acme.sh on your server … Read more

In CentOS, Red Hat Enterprise Linux (RHEL), and Fedora, you can install less by using the package manager yum. Here are the steps you can follow: Start by updating the package list by running the following command: sudo yum update Next, install less by running the following command: sudo yum install less Once the installation … Read more

In Linux, you can use the “>” symbol to redirect the output of a command to a file. Here’s an example of how you can use it: ls -l > file.txt This command will run the “ls -l” command and write the output to a file named “file.txt” in the current directory. You can also … Read more

In Ubuntu 20.04, you can set or change the Fully Qualified Domain Name (FQDN) by following these steps: First, open the /etc/hosts file by running the following command: sudo nano /etc/hosts Locate the line that starts with 127.0.0.1 and change the hostname to your desired FQDN, for example: 127.0.0.1 localhost.localdomain mynewfqdn Next, you will need … Read more

Unattended-upgrades is a package that allows Ubuntu to automatically download and install security updates and other important updates without any user intervention. This can be useful for servers or other systems that are running 24/7, as it ensures that the system remains up-to-date with security patches and other important updates. Ubuntu 20.04 includes an automatic … Read more