Varnish swallowing 4xx responses from POSTs

Tommy Becker twbecker at
Fri Sep 28 11:45:19 UTC 2018

Thanks! One last thing I will point out, is that in our case, 100-continue
doesn't help since we're responding due to a problem with the body itself.
My understanding of 100-continue is that it essentially okays the sender to
transmit the body.

On Fri, Sep 28, 2018 at 6:13 AM Dridi Boukelmoune <dridi at> wrote:

> 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.
> Dridi
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