Use Let's Encrypt To Secure Apache2 On Ubuntu - How to do it ?

This article covers method to Secure Apache with Let's Encrypt on Ubuntu 20.04. Let's Encrypt is a certificate authority created by the Internet Security Research Group (ISRG).

It provides free SSL certificates via a fully automated process designed to eliminate manual certificate creation, validation, installation, and renewal.

Certificates issued by Let's Encrypt are valid for 90 days from the issue date and trusted by all major browsers today.

To install Certbot on Ubuntu:

Certbot is a command-line tool that automates the tasks for obtaining and renewing Let’s Encrypt SSL certificates. 

The certbot package is included in the default Ubuntu repositories. 

Update the packages list and install certbot using the following commands:

$ sudo apt update
$ sudo apt install certbot

Before enabling the configuration files, make sure both mod_ssl and mod_headers are enabled by issuing:

$ sudo a2enmod ssl
$ sudo a2enmod headers

Next, enable the SSL configuration files by running the following commands:

$ sudo a2enconf letsencrypt
$ sudo a2enconf ssl-params

Enable the HTTP/2 module, which will make your sites faster and more robust:

$ sudo a2enmod http2

Reload the Apache configuration for changes to take effect:

$ sudo systemctl reload apache2

Verify if a Server Supports TLS or not on Ubuntu 20.04 - Step by Step Process ?

This article covers different methods to enable you find out if your specified web server is supporting TLS or not.
By so doing, you will be able to ensure whether your information is going to stay secure while using that web server or not.
TLS is an acronym for Transport Layer Security. TLS facilitates secure communication between computers on the Internet.
In this guide, we used both openssl and nmap.

To Verify TLS Support with Openssl:
Openssl is an open source tool for implementing secure communications on the Internet. The openssl tool is available on all major Linux distributions.
If the openssl tool is not already installed on your Linux machine, you may install it as follows.
On Ubuntu/Debian based distributions:

$ sudo apt install openssl

On CentOS/Red Hat based distributions:

$ sudo yum install openssl

Now, to verify TLSv1.3 support on your server or website, run the following command.

$ sudo openssl s_client -connect domain.com:443 -tls1_3

Install Microsoft PowerShell in Ubuntu 20.04 - How to perform this task ?

This article covers the different methods for installing Microsoft PowerShell on Ubuntu which includes installation via package repository, via .deb package, and via snap. 

PowerShell for Linux is published to package repositories for easy installation and updates. 

As superuser, register the Microsoft repository once. 

After registration, you can update PowerShell with sudo apt-get install powershell.

To install PowerShell on Ubuntu 20.04:

PowerShell for Linux is published to package repositories for easy installation and updates.

So do the following;

1. # Update the list of packages.

$ sudo apt-get update

2. # Install pre-requisite packages.

$ sudo apt-get install -y wget apt-transport-https software-properties-common

3. # Download the Microsoft repository GPG keys.

$ wget -q https://packages.microsoft.com/config/ubuntu/20.04/packages-microsoft-prod.deb

4. # Register the Microsoft repository GPG keys.

$ sudo dpkg -i packages-microsoft-prod.deb

5. # Update the list of products.

$ sudo apt-get update

6. # Enable the "universe" repositories.

$ sudo add-apt-repository universe

7. # Install PowerShell.

$ sudo apt-get install -y powershell

8. # Start PowerShell.

$ pwsh

As superuser, register the Microsoft repository once.

After registration, you can update PowerShell with sudo apt-get install powershell.

To remove PowerShell from Ubuntu:

Run the command,

$ sudo apt-get remove powershell

How to Launch PowerShell on Linux or Mac?

1. Open a terminal and run the "powershell" command to access a PowerShell shell environment. 

2. This works on both Linux and Mac–whichever you're using. 

3. You'll see a PowerShell prompt beginning with "PS", and you can run PowerShell cmdlets just as you would on Windows.

Commands to list installed rpm packages on Linux

This article will guide you on the different commands to list all installed rpm packages on CentOS, RHEL (Red Hat Enterprise Linux), SUSE/OpenSUSE and other rpm based distros using rpm and dnf/yum command that print a list of all installed packages on your distro.

Setting up Let's Encrypt SSL for domains hosted on an Apache web server based on CentOS 7

Let's Encrypt has gained popularity because they offer free SSL for millions of websites all over the world. They are a non-profit certificate authority run by Internet Security Research Group (ISRG) that provides X. 509 certificates for Transport Layer Security (TLS) encryption free of charge. The certificate is usually valid for 90 days after which is expires pending when it is renewed.