What Is a Web Server in Linux?

What is Linux?

Linux is a free operating system. An operating system is the main program that runs a computer, like Windows on a laptop. Linux is popular for servers because it is stable, safe and free.

What is a web server in Linux?

It is a Linux computer running a web server program. The program waits for visitors and sends them your pages. The two most common programs are:

• Apache, called apache2 on Debian and Ubuntu, and httpd on CentOS, AlmaLinux and similar.
• Nginx, known for speed.

Many people build a "LAMP" set: Linux, Apache, MySQL and PHP.

Steps to install Apache on Ubuntu or Debian

1. Connect to your server with SSH. SSH is a safe way to open a text window on your server from your computer.
2. Update the package list:

sudo apt update

This fetches the latest list of software you can install.

3. Install Apache:

sudo apt install apache2

This downloads and installs the web server.

4. Check that it is running:

sudo systemctl status apache2

It should say active (running).

5. Open your server's IP address in a browser. You should see a default welcome page.

On CentOS-style systems, use sudo dnf install httpd and sudo systemctl start httpd instead.

Where the files go

• On Debian and Ubuntu, site files go in /var/www/html.
• Apache settings are in /etc/apache2. On CentOS-style systems they are in /etc/httpd.

Useful basics

• A firewall may block web traffic. Allow ports 80 and 443.
• Add an SSL certificate so your site uses https.
• Keep the system updated.

Warning: Do not edit settings files without a backup copy. A typo can stop the server from starting.

Quick recap

• A Linux web server is Linux plus a web server program like Apache or Nginx.
• Install with apt or dnf as root.
• Site files live in /var/www/html on Debian and Ubuntu.
• Open ports 80 and 443 and add SSL.