Varnish swallowing 4xx responses from POSTs

Dridi Boukelmoune dridi at
Fri Sep 28 10:12:23 UTC 2018

On Fri, Sep 28, 2018 at 3:08 AM Tommy Becker <twbecker at> wrote:
> Hi Dridi,
> Thanks for the response. I’m curious what specifically you believe to be in violation of the spec here. There’s a lot of ambiguity to be had by my read, but the option to send responses at any point seems pretty clear. From RFC 7230 Section 6.5
>    A client sending a message body SHOULD monitor the network connection
>    for an error response while it is transmitting the request.  If the
>    client sees a response that indicates the server does not wish to
>    receive the message body and is closing the connection, the client
>    SHOULD immediately cease transmitting the body and close its side of
>    the connection.

That's a SHOULD I didn't remember, that's why ;)

> I should point out I initiated a thread on the Jetty mailing list on this same topic prior to this one, and they (perhaps unsurprisingly) defend this behavior. Greg Wilkins of the Jetty team asked me to relay this message in particular:

Thank you for relaying it. In the github issue you mentioned earlier I
already suggested 100-continue support (mentioned by Greg Wilkins) in
Varnish, but I wasn't aware/didn't remember the section you pasted.

> As I mentioned in that thread, I have no horse in this race and just want to solve my problem and perhaps spare others from this same issue, which was rather tough to debug.

Yes, and thank you for posting to the list. So this is neither a bug
in Varnish or Jetty, and we don't use Github issues for feature
requests. I will try to bring this up on Monday for the bugwash since
this feature would be a latency win.


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