Bug ID 631862: Stream is not finalized when OWS response has Transfer-Encoding header with zero-size chunk

Last Modified: Nov 07, 2022

Bug Tracker

Affected Product:  See more info
BIG-IP LTM(all modules)

Known Affected Versions:
11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5, 11.6.0 HF6, 11.6.0 HF7, 11.6.0 HF8, 11.6.1, 11.6.1 HF1, 11.6.1 HF2, 11.6.2, 11.6.2 HF1, 11.6.3,,,,, 11.6.4, 11.6.5,,,, 12.0.0, 12.0.0 HF1, 12.0.0 HF2, 12.0.0 HF3, 12.0.0 HF4, 12.1.0, 12.1.0 HF1, 12.1.0 HF2, 12.1.1, 12.1.1 HF1, 12.1.1 HF2, 12.1.2, 13.0.0, 13.0.0 HF1, 13.0.0 HF2, 13.0.0 HF3

Fixed In:
13.0.1, 12.1.2 HF1

Opened: Dec 05, 2016
Severity: 3-Major
Related Article:


When OWS sends a chunked response and the only chunk has a zero size, HTTP2 profile receives neither the response's body nor indication that the response has zero size.


On a stream with such response, BIG-IP doesn't generate a frame which would have END_STREAM flag. Some browsers may not handle the response properly. For example, a redirect may not be performed when the stream is not finalized. It results in incorrect page rendering on a client.


A virtual server must have HTTP2 profile, and OWS must serve a response with Transfer-Encoding: chunked and a zero size chunk (empty body).


Use following iRule for broken URLs: when HTTP_RESPONSE { if {[HTTP::header exists "Transfer-Encoding"] && [HTTP::status] eq 301} { HTTP::respond 301 -version 1.1 noserver Location [HTTP::header Location] Date [HTTP::header Date] Content-Type [HTTP::header Content-Type] Connection [HTTP::header Connection] } } A condition may be changed to narrow the iRule for specific URLs. HTTP::respond may be modified to include other important headers and serve a proper status code.

Fix Information

When OWS serves Transfer-Encoding chunked with zero size chuck, BIG-IP properly handles the response and sends END_STREAM flag finalizing the response.

Behavior Change