What is TCPdump

This flexible and powerful command-line tool helps in network troubleshooting. Tcpdump is a command-line utility that enables the collection and analysis of network traffic traversing the system. It is frequently used for network troubleshooting and as a security tool. TCPdump is a robust and flexible tool with numerous settings and filters that can be used in several situations. Since it is a command-line tool, it is suitable for running on distant servers or devices that lack a graphical user interface to collect data for subsequent analysis. It can be run in the background or scheduled with cron. This essay will discuss some of TCPdump’s most prevalent features.

Read our latest article about Network Protocols and learn more about TCP/UDP protocols.

Capturing packets with TCPdump

TCPdump requires elevated rights to collect packets for troubleshooting or analysis, so most commands in the following examples are started with sudo.
Use the following command to get started for a list of interfaces that can be captured:

tcpdump --list-interfaces

or

sudo tcpdump -D

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What is LEMP Stack

LEMP (Linux, NGINX, MySQL, PHP) is a software stack that used to be the environment for Websites and Web-applications which uses Linux as the Operating system, NGINX (Engine-X) as the web-server, MySQL as the database management system, and PHP as the Scripting language. is almost like LAMP stack with one main difference in the web-server application, in the LEMP stack we use NGINX as the web-server application which is more flexible and lightweight than Apache.

Install NGINX

For installing NGINX on Ubuntu 20.04 you can install it using the official “apt” repository.

apt install nginx

You can start the Nginx service using systemctl also you can make it run at the system startup:

systemctl start nginx

systemctl enable nginx

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What is LEMP Stack

LEMP (Linux, NGINX, MySQL, PHP) is a software stack that used to be the environment for Websites and Web-applications which uses Linux as the Operating system, NGINX (Engine-X) as the web-server, MySQL as the database management system, and PHP as the Scripting language. is almost like LAMP stack with one main difference in the web-server application, in the LEMP stack we use NGINX as the web-server application which is more flexible and lightweight than Apache.

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What is Chrony

Chrony is the default NTP server/client on RHEL/CentOS 8 operating system. basically, Chrony is an implementation of the NTP (Network Time Protocol) and it performs well in a wide range of conditions. Chrony can be used to synchronize the system date and time with NTP servers.
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  Install LAMP Stack on CentOS 8

LAMP stack is a software stack that includes: Linux as a primary Operating system, Apache as a Web-Server, MySQL as a database, and PHP as a scripting language.
LAMP stack used to create an environment for Developing/Running PHP web applications and it’s one of the most popular software stacks out there. In this tutorial, we are going to learn how to install each one of the softwares of the LAMP Stack on the CentOS 8 machine.
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Install LAMP Stack on Ubuntu 20.04

LAMP stack is a software stack that includes: Linux as a primary Operating system, Apache as a Web-Server, MySQL as a database, and PHP as a scripting language.
LAMP stack used to create an environment for Developing/Running PHP web applications and it’s one of the most popular software stacks out there. In this tutorial, we are going to learn how to install each one of the softwares of the LAMP Stack on the CentOS 8 machine.
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What is NTP

NTP (Network Time Protocol) is a protocol used to synchronize computer times over a network, and it is one of the oldest TCP/IP protocol stack parts which is highly fault-tolerant and scalable. There are thousands of NTP servers around the world with access to highly precise atomic clocks and GPS clocks, NTP uses Coordinated Universal Time (UTC) to synchronize computer clock times with precision.
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Screen is a terminal program for Linux which allows you to multiplex your terminal window and manage them simultaneously. it allows you to access multiple terminal sessions within a single terminal session. this tool is most useful when you are connected to a Linux system remotely like SSH sessions when you want to do multiple things and without Screen you need to do them one by one but using Screen you can do multiple things simultaneously. Screen also lets multiple remote systems connect to a specific screen session at once.
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SSH (also referred to as Secure Shell) is a protocol for remote login to a system securely. SSH provides several alternative options for strong authentication, and it protects the communications from both ends with strong encryptions. SSH is a secure alternative to non-protected protocols such as telnet or rlogin, and it also can provide file transfer services more securely than other common protocols.

In this article, we are not going to talk about obvious things such as “choosing strong passwords” etc. the more technical security hardening methods is the point of this tutorial.
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