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Fwd: Question on CURLE_RECV_ERROR (56)

From: ghanashyam satpathy via curl-users <>
Date: Wed, 10 Jan 2018 11:01:10 +0530

Following are the library version I am using.

libcurl - 7.50.3
openssl - 1.1.0 b
McAfee WebGateway

Very much reproducible using Fiddler as a proxy that requires
authentication(basic), just supply invalid credential to libcurl.
The curl_easy_perform() will return CURLE_RECV_ERROR (56)


On Thu, Jan 4, 2018 at 10:03 AM, Daniel Stenberg <> wrote:

> On Wed, 3 Jan 2018, ghanashyam satpathy via curl-users wrote:
> Please don't reply to digest mails to start a new conversation and please
> don't full-quote a totally irrelevant email when you do.
> I have a question on CURL error code in following scenario:
>> I am using an authenticated(NTLM) HTTP proxy. And intentionally supplied
>> wrong credential.
>> curl_easy_perform() returned me CURLE_RECV_ERROR (56)
>> *Any idea how to get correct error code in such scenario. It should return
>> something Access Denied or Authentication failed..*
> You don't give us enough information to tell. Like your "curl -V" output
> that would tell us your curl version and what TLS library that's being used
> and some clues on what backend that is for your NTLM use.
> In curl we make an effort to return the correct error code for all error
> sitations but sometimes we have a bug and sometimes the underlying API from
> the function we use in the system or 3rd party library doesn't give the
> information clearly enough for us to differentiate between different
> situations in the way we'd prefer.
> --
> /

Received on 2018-01-10