cURL / Mailing Lists / curl-library / Single Mail


Re: Connection getting closed on receiving 401 from server during POST

From: Vivek S <>
Date: Mon, 16 Jun 2014 12:25:13 +0530

> So can you elaborate on why using libcurl's own NTLM powers isn't enough?

Our application acts as a proxy and has option to do NTLM
authentication with server on behalf of clients. Here, we could use
curl's NTLM option without any issues.
Also, our application has another mode in which it acts as
transparent-proxy by just relaying the headers and body between client
and server. In this case, we don't control headers, allowing actual
client to authenticate over NTLM.

So in this second mode, we don't have option to use curl's NTLM option
as we don't have credentials; but have to maintain the connection for
NTLM handshake to complete. This is the point where libcurl closes the
connection on seeing 401 (when receiving NTLM challenge-2) and making
NTLM authentication to fail during POST/OPTIONS requests.

I think, I can generalize the problem as current libcurl cannot proxy
(in sense, relaying the data) NTLM authentications in all requests

Hope I have given enough details on why libcurl's NTLM can't be used
in some situations.
Or if you believe there exists some way, which we are not aware of, to
achieve this, I would be glad to to know it.

- Vivek S
List admin:
Received on 2014-06-16