HTTP 206 status code

206 Partial Content indicates that the server has successfully processed part of the GET request. HTTP download tools like FlashGet or Thunder use this type of response to resume interrupted downloads or break a large document into multiple download segments for simultaneous downloading.

The request must include the Range header information to indicate the content range the client wants to get, and may include If-Range as the request condition.

The response must contain the following header fields:

Content-Range is used to indicate the range of content returned in this response; if it is a multi-part download with Content-Type multipart/byteranges, Then each multipart section should contain a Content-Range field to indicate the content range of this section. If a Content-Length is included in the response, its value must match the actual number of bytes in the content range it returns.

Date

ETag and/or Content-Location, if the same request should have returned a 200 response.

Expires, Cache-Control, and/or Vary if its value may be different from the value corresponding to other previous responses to the same variable.

If this response request uses If-Range strong cache verification, then this response should not contain other entity headers; if this response request uses If-Range weak cache verification, then this response is prohibited from containing Other entity headers; this avoids inconsistencies between cached entity content and updated entity header information. Otherwise, this response should contain all entity header fields that should be returned in a 200 response.

If the ETag or Last-Modified header does not match exactly, the client cache should not combine the content returned by the 206 response with any previously cached content.