diff --git a/guides/source/action_controller_overview.md b/guides/source/action_controller_overview.md
index 826d25d173..36d1b6de83 100644
--- a/guides/source/action_controller_overview.md
+++ b/guides/source/action_controller_overview.md
@@ -994,6 +994,11 @@ you would like in a response object. The `ActionController::Live` module allows
 you to create a persistent connection with a browser. Using this module, you will
 be able to send arbitrary data to the browser at specific points in time.
 
+NOTE: The default Rails server (WEBrick) is a buffering web server and does not
+support streaming. In order to use this feature, you'll need to use a non buffering
+server like [Puma](http://puma.io), [Rainbows](http://rainbows.bogomips.org)
+or [Passenger](https://www.phusionpassenger.com).
+
 #### Incorporating Live Streaming
 
 Including `ActionController::Live` inside of your controller class will provide