HTTP/2 is the latest version of the Hypertext Transfer Protocol, designed to improve website loading speed and overall performance. With multiplexed streams, header compression, and server push features, HTTP/2 can significantly enhance user experience. In this guide, we’ll walk you through the steps to enable HTTP/2 on your Linux server, covering installation and configuration for both Apache and Nginx.

Prerequisites

Before you start, ensure you have the following:

  1. Linux Server: A running instance of a Linux distribution (Ubuntu, CentOS, etc.).

  2. Root Access: You need root privileges to install and configure packages.

  3. Web Server: Either Apache or Nginx installed and configured for your website.

  4. SSL Certificate: HTTP/2 requires HTTPS. You can obtain a free SSL certificate from Let’s Encrypt.

Step 1: Update Your System

Before making any changes, it’s crucial to update your package manager:

sudo apt update && sudo apt upgrade -y  # For Debian/Ubuntu

sudo yum update -y                      # For CentOS

Step 2: Install/Verify SSL Certificates

Your web server needs a valid SSL certificate. For simplicity, you can use Certbot to obtain a free SSL certificate:

# Install Certbot

sudo apt install certbot python3-certbot-apache -y  # For Apache

sudo apt install certbot python3-certbot-nginx -y    # For Nginx



# Obtain a certificate (replace example.com with your domain)

sudo certbot --apache -d example.com                    # For Apache

sudo certbot --nginx -d example.com                     # For Nginx

Follow the prompts to confirm your email and agree to the terms of service.

Step 3: Enable HTTP/2 on Apache

3.1 Check Your Apache Version

Ensure that your Apache version is 2.4.17 or later, as HTTP/2 support is included from this version onwards:

apache2 -v  # For Debian/Ubuntu

httpd -v    # For CentOS

3.2 Enable the mod_http2 Module

Run the following commands to enable HTTP/2 support:

sudo a2enmod http2

3.3 Configure HTTP/2 in Your Apache Config

Open your Apache configuration file or the specific virtual host file (e.g., /etc/apache2/sites-available/example.conf):

sudo nano /etc/apache2/sites-available/example.conf

Add the following line inside the <VirtualHost *:443> block:

Protocol h2 http/1.1

After editing, your virtual host configuration should look like this:

<VirtualHost *:443>

    ServerName example.com

    DocumentRoot /var/www/html



    # ... Other directives



    Protocol h2 http/1.1

</VirtualHost>

3.4 Restart Apache

To apply your changes:

sudo systemctl restart apache2

Step 4: Enable HTTP/2 on Nginx

4.1 Check Your Nginx Version

Ensure your Nginx version is 1.13.0 or later:

nginx -v

4.2 Configure HTTP/2 in Your Nginx Config

Open your Nginx configuration file or the specific server block file (e.g., /etc/nginx/sites-available/example):

sudo nano /etc/nginx/sites-available/example

Locate the line that begins with listen 443 and modify it to include http2:

server {

    listen 443 ssl http2;

    server_name example.com;

    root /var/www/html;



    # ... Other directives

}

4.3 Test Your Configuration

Before restarting Nginx, test your configuration for syntax errors:

sudo nginx -t

4.4 Restart Nginx

If there are no errors, restart Nginx to apply the changes:

sudo systemctl restart nginx

Step 5: Verify HTTP/2 is Working

To check if HTTP/2 is enabled, you can use a browser developer tool or an online service like tools.keycdn.com/http2-test.

Alternatively, use cURL:

curl -I -s --http2 https://example.com | grep HTTP

If successful, you should see HTTP/2 in the output.

Conclusion

Congratulations! You’ve successfully enabled HTTP/2 on your Linux server. This upgrade can enhance your website’s performance and provide a better user experience. Regularly monitor your server and application performance to reap the full benefits of HTTP/2.

For further reading and advanced configuration, check out the official documentation for Apache and Nginx.