Disable ipv6 on Linux Machine

Disable on Centos/RHEL system:

1. Append below lines in /etc/sysctl.conf:

net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1

NOTE : To disable IPv6 on a single interface add below lines to /etc/sysctl.conf :

net.ipv6.conf.[interface].disable_ipv6 = 1 ### put interface name here [interface]
net.ipv6.conf.default.disable_ipv6 = 1

2. To make the settings affective, execute :

# sysctl -p

Disable on Debian/Ubuntu system:

One method to make this option persist is modifying /etc/sysctl.conf.  Add the following lines to the file:

net.ipv6.conf.all.disable_ipv6=1
net.ipv6.conf.default.disable_ipv6=1
net.ipv6.conf.lo.disable_ipv6=1

For the settings to take effect use:

sudo sysctl -p
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Install Development Tool on CentOS and Debian

Well, in my working domain I face these tools to be installed, so that most of the dependent tools or programs that need to be deployed later don’t face much of dependency issue. So here goes the installation process for both the OS.

On CentOS/RHEL system use the follwoing command (either one of it would work)-

Type the following yum command as root user:

# yum group install "Development Tools"

Continue reading “Install Development Tool on CentOS and Debian” »

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Delete Old Unused Kernels in Debian

To find out the current version of Linux kernel running on your system, use the following command.

$ uname -sr
Linux 4.12.0-041200-generic

To list all installed kernels on your system, issue this command.

$ dpkg -l | grep linux-image | awk '{print$2}'

linux-image-4.12.0-041200-generic
linux-image-4.8.0-22-generic
linux-image-extra-4.8.0-22-generic
linux-image-generic

Remove Old Unused Kernels on Debian and Ubuntu

Run the commands below to remove a particular linux-image along with its configuration files, then update grub2 configuration, and lastly reboot the system.

$ sudo apt remove --purge linux-image-4.4.0-21-generic
$ sudo update-grub2
$ sudo reboot
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Reset Root Password on Ubuntu 20

Step 1: Reboot your Ubuntu 20.04 LTS Operating System and load the GRUB menu by holding the Shift Key on Keyboard

The first step is to start your computer machine and keep pressing the shift button on your keyboard until the GRUB menu appears, as shown in the picture below:

Step 2: Press ‘e’ to edit the commands

Now, select the boot Operating system, which is Ubuntu in our case, and press the ‘e’ key on your keyboard to edit some commands. By doing so, we can load the root shell Command prompt. Pressing the ‘e’ key on your keyboard allows you to have an edit screen, as shown in the picture below: Continue reading “Reset Root Password on Ubuntu 20” »

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Creating a Sudo User in Debian or Ubuntu

Creating a Debian Sudo User

Creating a Debian sudo user involves a few simple steps. This procedure does not require you to edit the sudoers file. If you have an existing user that you want to grant sudo privileges, skip Step 2.

Step 1: Log in as the Root User

Before you can add a user to your system, log in to your server as the root user:

ssh root@ip_address

Replace ip_address with the IP address of your server. Continue reading “Creating a Sudo User in Debian or Ubuntu” »

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Remove Old Kernels of Debian/Ubuntu

To find out the current version of Linux kernel running on your system, use the following command.

$ uname -sr
Linux 4.12.0-041200-generic

To list all installed kernels on your system, issue this command.

$ dpkg -l | grep linux-image | awk '{print$2}'

linux-image-4.12.0-041200-generic
linux-image-4.8.0-22-generic
linux-image-extra-4.8.0-22-generic
linux-image-generic

Remove Old Unused Kernels on Debian and Ubuntu

Run the commands below to remove a particular linux-image along with its configuration files, then update grub2 configuration, and lastly reboot the system.

$ sudo apt remove --purge linux-image-4.4.0-21-generic
$ sudo update-grub2
$ sudo reboot

Removing Old Kernel in Ubuntu Continue reading “Remove Old Kernels of Debian/Ubuntu” »

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Install phpIPAM on Ubuntu 20.04/18.04

The objective of this guide is to help you Install and Configure phpIPAM on Ubuntu 20.04/18.04 Linux distribution. phpIPAM is an open-source php-based web IP address management application (IPAM). Its goal is to provide light, modern and useful IP address management. phpIPAM uses MySQL database backend and jQuery libraries, Ajax and HTML5/CSS3 features.

Install phpIPAM on Ubuntu 20.04/18.04

phpIPAM has a number of dependencies that we need to install before we can install and configure phpIPAM. These are:

  • MySQL / MariaDB server
  • php / php-fpm for nginx
  • php modules
  • Apache / nginx web server
  • phpIPAM domain – ipam.example.com (should be replaced with your domain)

Continue reading “Install phpIPAM on Ubuntu 20.04/18.04” »

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Install Virtualbox 5.2/6.1 on Ubuntu 16 headless mode

Install Prerequisites

Before installing VirtualBox 5.2/6.1, please install these packages below if your systems don’t already have them installed….

sudo apt update
sudo apt-get install gcc make linux-headers-$(uname -r) dkms

Add VirtualBox Repository

If you want to always get the latest versions of VirtualBox when they become available, you’ll want to add its software repository to Ubuntu…

Run the commands below to add the repository key to your system…

wget -q https://www.virtualbox.org/download/oracle_vbox_2016.asc -O- | sudo apt-key add -
wget -q https://www.virtualbox.org/download/oracle_vbox.asc -O- | sudo apt-key add -

After adding the repository key above, run the commands below to add VirtualBox package repository.

sudo add-apt-repository "deb [arch=amd64] http://download.virtualbox.org/virtualbox/debian $(lsb_release -cs) contrib"

After that, run the commands below to update Ubuntu repositories.

Installing VirtualBox

At this point, the Ubuntu system should be ready to install the latest version of VirtualBox. First you may want to remove the previous 6.0 version if you’re still running it… to do that, run the commands below:

sudo apt remove virtualbox virtualbox-6.1

Finally, run the commands below to install the latest 6.1 (major) version of the software. Continue reading “Install Virtualbox 5.2/6.1 on Ubuntu 16 headless mode” »

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Install LAMP with PHP-FPM on Ubuntu 20

Step 1 – Installing Apache

Apache web server debian packages are available under the default repositories. Login to your Ubuntu system with sudo privileges account. Open a terminal and execute the following commands:

sudo apt update 
sudo apt install apache2 libapache2-mod-fcgid

The above commands will install Apache and FastCGI module to your server.

Step 2 – Install PHP with FPM

Next, install PHP and PHP-FPM on your Ubuntu system. For this tutorial, we choose PHP 7.4 to install using

For the PHP installation we recommend to use ppa:ondrej/php PPA. Execute below couple of commands to add the PPA to your system.

sudo apt install software-properties-common
sudo add-apt-repository ppa:ondrej/php

Then install PHP 7.4 (or required version) the latest version available on the day of writing this tutorial. Simply execute follows commands for the installation of PHP and PHP-FPM packages. Continue reading “Install LAMP with PHP-FPM on Ubuntu 20” »

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