How to enable HTTP/2 for Apache

HTTP/2 is a major improvement over HTTP/1.1 especially in the speed department. HTTP/2 is supported by Apache though it's not enabled by default.

HTTP/2 could simply be enabled on Apache by installing required module and configure Apache to serve requests using HTTP/2 instead of the default HTTP/1.1

Steps to enable HTTP/2 on Apache:

1. Launch terminal application.
2. Enable http2 module for Apache.

   $ sudo a2enmod http2 # Ubuntu and Debian
   [sudo] password for user:
   Enabling module http2.
   To activate the new configuration, you need to run:
     systemctl restart apache2

   How to enable or disable Apache modules

3. Add relevant Protocols directive in main Apache configuration file or on a specific virtual server configuration.

   <VirtualHost *:80>
           # .....
           # ....
           Protocols h2 h2c http/1.1
   </VirtualHost>

   Apache configuration files

   Configuration options for HTTP/2

4. Restart Apache service for the changes to take effect.

   $ sudo systemctl restart apache2 # Ubuntu and Debian
   $ sudo systemctl restart httpd # CentOS and Red Hat

   How to start, restart and stop Apache service

5. Test by accessing the service using curl.

   $ curl --http2 --head  www.simplified.guide
   HTTP/1.1 101 Switching Protocols
   Upgrade: h2c
   Connection: Upgrade
   
   HTTP/2 200
   date: Sun, 00 Jan 1900 00:00:00 GMT
   server: Apache/2.4.41 (Ubuntu)
   last-modified: Sat, 08 Feb 2020 14:15:13 GMT
   etag: W/"2aa6-59e11227347f6"
   accept-ranges: bytes
   content-length: 10918
   vary: Accept-Encoding
   content-type: text/html