Apache: Configure for HTTP/2

Configure Apache to use HTTP/2 protocol.

The HTTP/2 protocol has enhancements that improve the speed in which pages load in web browsers. The HTTP/2 protocol is available over unencrypted (http://) and encrypted (https://) channels, but most major browsers only support use of HTTP/2 over HTTPS. Therefore, you need to ensure HTTPS is enabled on your server.

Ensure your Apache is version 2.4.17 or greater.

Let the client define the protocol

For Apache, the following directives configure HTTP/2:
ProtocolsHonorOrder On
Protocols h2 http/1.1

With these directives, ProtocolsHonorOrder On means that Apache chooses the protocol and HTTP/2 is the first choice.

However, the recommendation is that the client define the preferred protocol. This will allow the GAS to work with services that may not need the HTTP/2 protocol. This will also avoid an error where a client that does not support HTTP/2 receives the following response from the server:

Upgrade: h2
Connection: Upgrade

Follow this procedure to configure Apache with the directive ProtocolsHonorOrder Off, allowing the client to select the protocol.

  1. Find the Apache configuration file (for example, httpd.conf). It is likely to be located in the /etc/apache2/ path.
  2. Ensure the module http2_module is enabled.
  3. Set these directives. 
    ProtocolsHonorOrder Off
Protocols h2 http/1.1