firewalld is the default firewall on Red Hat Enterprise Linux, and it’s enabled by default, but it’s possible to disable the firewall on Redhat, and you’ll also see how to check firewall status in Linux. Normally, there should not be a need to disable the firewall, but it may be quite handy for testing purposes or other scenarios. In this tutorial, you’ll see how to check the status of firewalld, enable or disable the service from starting automatically upon system boot, and how to stop or start the firewalld service in RHEL.
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Getting started with Toolbx
Fedora Silverblue is an immutable variant of Fedora Workstation: every installation of this distribution is identical to the others, which is ideal for testing and predictability. On Fedora Silverblue, flatpaks are used as the primary method of installing software together with rpm-ostree which basically creates an additional layer over the immutable filesystem each time an rpm is installed. The toolbx utility is included in Fedora Silverblue as a way to create isolated, mutable environments using podman and the containers technology, allowing the user to install development tools and libraries without touching the main system. Toolbx can be used also on regular Fedora versions.
How to check CentOS version
The purpose of this tutorial is to show how to check the CentOS version of your Linux system. It’s possible to do this from either command line or GUI, so you can use whichever method is more convenient for you. Classic CentOS is nearing its end of life and will be replaced by CentOS Stream. Knowing your CentOS version will give you some insight into how long your system will continue to be supported.
How to fix: user not in sudoers file error
The purpose of this tutorial is to show how to fix the RHEL7 User Not In Sudoers File Error on all major Linux distributions. When trying to execute Linux commands with root privileges via the sudo command, you will receive an error message if the current user is not in the sudoers file. This is a security feature on Linux systems to stop ordinary users from esclating their commands to administrator privileges.
How to perform unattended Linux installations with Kickstart
Kickstart is an automatic installation method natively available on those distributions which uses the Anaconda installer: Red Hat Enterprise Linux (and its clones) and Fedora. It can also be used to install Ubuntu, actually, but in that context it acts as a layer of compatibility to the debian-native preseeding method. With Kickstart we can perform unattended, customizable and reproducible installations.
Check RPM package dependencies on Rhel/Centos/Rocky
Files with the .RPM extension are software packages intended for installation on Red Hat Enterprise Linux or one of its derivative Linux distributions, such as CentOS, AlmaLinux, Rocky Linux, or Fedora. When you install software by using an RPM file, your system may need to install dependencies for it to run correctly. This is common behavior for the dnf package manager as well, so you may already be familiar with package dependencies. In this tutorial, we will show you how to check the package dependencies for an RPM file on RHEL and similar distros.
How to open SSH port 22 on Rehdat 7 Linux server
The SSH protocol operates on port 22 by default. In order to accept incoming connections on your Red Hat 7 Linux SSH server, you will need to ensure that port 22 is allowed through the firewall. This will involve opening the port in firewalld, the default firewall interface for Red Hat.
KDE Desktop installation on RHEL 7 Linux
By default, the Red Hat Enterprise Linux distribution sports the GNOME desktop environment, or no GUI at all. If you would like to change things up and install KDE Plasma instead, the GUI can be downloaded and installed directly from Red Hat’s package repositories.
How to change runlevel on RHEL 7 Linux
The conventional way used to change the runlevel with /etc/inittab has become obsolete with Red Hat Enterprise Linux version 7. As a result, any Linux system using systemd system management daemon now relies on the systemctl command to change runlevel – or, to be more precise, to change the target. Therefore any edits to the /etc/inittab file will not take effect on RHEL 7.
How to change a hostname on Redhat 7 Linux
The hostname of your Red Hat Enterprise Linux system is important because it’s used to identify the device on a network. The hostname is also shown in other prominent places, such as in the terminal prompt. If you have not bothered to change the hostname yet, your system probably bears the default localhost.localdomain name, which is not very helpful.
httpd: apr_sockaddr_info_get() failed on RHEL
When running an Apache web server on Red Hat Enterprise Linux, you may encounter the error AH00557: httpd: apr_sockaddr_info_get() failed or AH00558: httpd: Could not reliably determine the server's fully qualified domain name when trying to start the service. In this tutorial, we will look into the cause of this error and give you a solution for fixing it.
There are no enabled repositories RHEL solution
You may receive a There are no enabled repos error message when trying to install system updates on a fresh Red Hat Linux install. This occurs when you have not enabled your RHEL subscription. In this tutorial, we will take you through the step by step instructions to register your RHEL subscription, enable the package manager, and finally install updates and remedy the error message for good.