What does the HTTP 206 Partial Content status message mean and how do I fully load resources?

From user166390’s answer to the question Why does Firebug show a "206 Partial Content" response on a video loading request?

This Partial Content code (206) may be sent from the server when the client has asked for a range (e.g. "give me the first 2MB of video data").

It is vital for downloading data in chunks which avoids fetching unused resources. (I seldom watch a full video online.) Look at the outgoing request for a Range header.

It's up to the client to put in another call to get the rest of the data (or the next bit). You don't have to do anything, they'll get the full image eventually, even if it takes several http calls.

Firstly:

The HTTP 206 Partial Content success status response code indicates that the request has succeeded and has the body contains the requested ranges of data, as described in the Range header of the request.

If there is only one range, the Content-Type of the whole response is set to the type of the document, and a Content-Range is provided.

If several ranges are sent back, the Content-Type is set to multipart/byteranges and each fragment covers one range, with Content-Range and Content-Type describing it.

(From Mozilla's excellent HTTP status code reference.)

Next:

HTTP headers set on resources are usually set by the web server. However if the file is large, like a video file the browser can request a chunk of the resource that is being loaded. Usually a HTTP 206 header will be returned from a client initiated request. The headers set on resources in apache are set in the mod_headers section of the httpd.conf. Look for the following line to see if partial content is turned on:

Header set Accept-Ranges bytes

This section controls the behavior of headers set by apache so it will be a good place to start.

Setting the headers can however be done in a number of different ways. For example when using apache you can control the images that are loaded so that they will cache. This can be done using the [a2enmod module][2]. This will reduce the load on your server.