Hypertext Transfer Protocol Version 2 (HTTP/2) is the latest version of the HTTP protocol, published as an IETF standard in RFC 7540 in 2015. The focus of the protocol is on performance; specifically, end-user perceived latency, network and server resource usage. One major goal is to allow the use of a single connection from browsers to a Web site. The protocol is backward compatible, so HTTP methods, status codes, and semantics are the same as for previous versions of the protocol. Apache has HTTP/2 support since version 2.4.17. In this tutorial, I'm going to assume that you already have a working TLS configuration, and that you have required Apache version installed on your Linux distribution of choice, and that you know how to use Let's Encrypt, or you know how to issue a self-signed certificate.
To enable HTTP/2 in Apache you will need to fulfill the following requirements:
- First, you need to enable HTTPS on your server. All major browsers allow using of HTTP/2 only over HTTPS. Also, TLS protocol version >= 1.2 with modern cipher suites is required.
- Next, ensure that you are running Apache 2.4.17 or above because HTTP/2 is supported from this version and upwards.
- Also, ensure that your client/browser actually supports HTTP/2.
Enable HTTP/2 support in Apache
To get HTTP/2 working on Apache you need to enable and load SSL and HTTP/2 modules. To do so, you may run the following in your terminal:
sudo a2enmod ssl
sudo a2enmod http2
To activate these new modules, you need to run:
sudo systemctl restart apache2
After enabling and loading necessary Apache modules, navigate to your Apache configuration directory and edit Apache configuration.
To enable HTTP/2 on your Apache web server add one of the following to your global Apache configuration or inside of a particular virtual host.
Protocols h2 http/1.1
Here is the minimal virtual server configuration that can be used to enable HTTP/2 in some virtual host:
SSLProtocol all -SSLv3 -TLSv1 -TLSv1.1
Protocols h2 http/1.1
To check if your server supports HTTP/2, you can use your browser and type the following https://example.com domain.