Convert .p12 bundle to server certificate and key files

Seperate Private Key and Certificate file

#Generate certificates bundle file

openssl pkcs12 -nokeys -in server-cert-key-bundle.p12 -out server-ca-cert-bundle.pem

#Generate server key file.

openssl pkcs12 -nocerts -nodes -in server-cert-key-bundle.p12 -out server.key

Convert a PKCS#12 file (.pfx .p12) containing a private key and certificates to PEM

openssl pkcs12 -in keyStore.pfx -out keyStore.pem -nodes

Create a .pfx/.p12 certificate file using OpenSSL

openssl pkcs12 -export -out certificate.pfx -inkey privateKey.key -in certificate.crt

Src: https://www.sslshopper.com/article-most-common-openssl-commands.html

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Email Alert for Host down using fping

A simplified bash script for host status alert:

#!/bin/bash

email=h.t.emdad@gmail.com
NBR_DOWN=0
LOGFILE=/tmp/pinglog.txt

echo "Server Down Status" > $LOGFILE
for i in $(cat ping.txt); do
fping $i >/dev/null
if [ $? -ne 0 ]; then
echo "$i is down" >> $LOGFILE
NBR_DOWN=$((NBR_DOWN+1))
fi
done

if [ $NBR_DOWN -gt 0 ]; then
mailx -s "Server Down Alert" $email < $LOGFILE
fi

The contents on ping.txt is like (entries are with new line entry:

core-router
host1
bc
host2
host3
host4
cpanel

If you do not have ‘mailx’ installed, install it using

yum install mailx.
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Install PHP 7.4 / 7.3 / 7.2 / 7.1 on Debian 10 / Debian 9

Add PHP Repository

SURY, a third-party repository which offers PHP 7.4 / 7.3 / 7.2 / 7.1 for Debian operating system.

By default, Debian 10 ships PHP v7.3. So, you can either install PHP v7.3 from Debian repository or SURY repository. Skip this section if you want to install PHP 7.3 from the Debian repository. However, if you want to install PHP 7.4 / 7.2 / 7.1 on Debian 10, you must set up SURY repository.

Update the repository cache.

sudo apt update
sudo apt install -y curl wget gnupg2 ca-certificates lsb-release apt-transport-https

Import the public using the below commands.

wget https://packages.sury.org/php/apt.gpg
sudo apt-key add apt.gpg

Add the SURY repository to your system.

echo "deb https://packages.sury.org/php/ $(lsb_release -sc) main" | sudo tee /etc/apt/sources.list.d/php7.list

Update the repository index. Continue reading “Install PHP 7.4 / 7.3 / 7.2 / 7.1 on Debian 10 / Debian 9” »

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Multiple or Two Default Gateways on One System

Problem Description

You have built two or more network cards into one Linux system and each of these cards has its own default gateway. By default, you can only have one default gateway on a system. The case described would lead to asynchronous routing, whereby the router would reject the packets as appropriate.

Solution

The iproute2 program, which is included in all current Linux distributions and already installed even, as a rule, can be used for the solution of this problem. Normally, a Linux system only has one routing table, in which only one default gateway can make entries. With iproute2, you have the ability to setup an additional routing table, for one thing, and allow this table to be used by the system based on rules, for another. Continue reading “Multiple or Two Default Gateways on One System” »

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How to find out the connected interface using linux command

Method 1

To find out the connected state of a network cable in Linux, just run:

$ cat /sys/class/net/enp5s0/carrier

Sample output:

1

If you got output as “1” (Number one), It means that the network cable is connected with the network card. Also, you can do this with the following command too:

$ cat /sys/class/net/enp5s0/operstate

Sample output: Continue reading “How to find out the connected interface using linux command” »

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Install LAMP on CentOS 7 with PHP 5.4/7.0/7.1/7.2/7.3/7.4

Preliminary Note

In this tutorial, I use the hostname server1.example.com with the IP p 192.168.0.100. These settings might differ for you, so you have to replace them where appropriate.

I will add the EPEL repo here to install latest phpMyAdmin as follows:

rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY*
yum -y install epel-release

To edit files on the shell, I’ll install the nano editor. If you prefer vi for file editing, then skip this step.

yum -y install nano

Installing MySQL / MariaDB

MariaDB is a MySQL fork of the original MySQL developer Monty Widenius. MariaDB is compatible with MySQL and I’ve chosen to use MariaDB here instead of MySQL. Run this command to install MariaDB with yum:

yum -y install mariadb-server mariadb

Then we create the system startup links for MySQL (so that MySQL starts automatically whenever the system boots) and start the MySQL server: Continue reading “Install LAMP on CentOS 7 with PHP 5.4/7.0/7.1/7.2/7.3/7.4” »

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Enable mod_rewrite for Apache on CentOS 7

The mod_rewrite module is enabled by default on CentOS 7. If you find it is not enabled on your server, you can enable it by editing 00-base.conf file located in /etc/httpd/conf.modules.d/ directory.

sudo nano /etc/httpd/conf.modules.d/00-base.conf

Add or uncomment the following line:

LoadModule rewrite_module modules/mod_rewrite.so

Save and close the file, then restart the httpd service:

sudo systemctl restart httpd

Enable .htaccess File

Once the mod_rewrite module has been activated, you can set up your URL rewrites by creating an .htaccess file in your default document root directory. A .htaccess file allows us to modify our rewrite rules without accessing server configuration files. For this reason, .htaccess is critical to your web server. Before we begin, we need to allow Apache to read .htaccess files located under the /var/www/html directory. Continue reading “Enable mod_rewrite for Apache on CentOS 7” »

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Virtualbox fixing VRDE on 0.0.0.0 instead 127.0.0.1

By default, Remote Display only works on localhost / 127.0.0.1 and cannot be accessed by ip address or hostname.

Check VRDE / Remote Display IP Address
You can check VRDE / Remote Display ip address using the following methods:

Open command prompt and run netstat -an |find /i “listening” or netstat -an |find /i “[PORT_NUMBER]” and you shall notice it is listening on 127.0.0.1:PORT. Continue reading “Virtualbox fixing VRDE on 0.0.0.0 instead 127.0.0.1” »

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Installing MySQL on Debian

Step 1 – Prerequisites

Login to your Debian 9 system using shell access. For remote systems connect with SSH. Windows users can use Putty or other alternatives applications for SSH connection.

ssh root@debian9

Run below commands to upgrade the current packages to the latest version.

sudo apt update 
sudo apt upgrade

Step 2 – Configure MySQL PPA

MySQL team provides official MySQL PPA for Debian Linux. You can download and install the package on your Debian system, which will add PPA file to your system. Run below command to enable PPA.

wget http://repo.mysql.com/mysql-apt-config_0.8.13-1_all.deb
sudo dpkg -i mysql-apt-config_0.8.13-1_all.deb

During the installation of MySQL apt config package, It will prompt to select MySQL version to install. Select the MySQL 5.7 or 5.6 option to install on your system. Continue reading “Installing MySQL on Debian” »

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Remove Node from Proxmox Cluster

Step 1 : Migrate all VMs to another active node

Migrate all VMs to another active node. You can use the live migration feature if you have a shared storage or offline migration if you only have local storage.

Step 2 : Display all active nodes

Display all active nodes in order identify the name of the node you want to remove Continue reading “Remove Node from Proxmox Cluster” »

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