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Re: Problem with NTLM proxy authentication

From: Ulrich Telle <>
Date: Fri, 05 Sep 2014 12:26:45 +0200


> > I scheduled testing of the authentication process, that includes a
> > guy watching on the proxy server side, logging the network traffic
> > during the tests.
> Okay cool - it will be interesting to see how you get on and what
> information comes out of that.

It took a bit longer than expected to arrange and perform the tests, but now
the tests took place.

Although the tests failed again, we gained a bit of knowledge from the
additional debug messages I added.

> Sure - if it is a problem in libcurl I would like to be able to
> resolve it as well. So any assistance you can provide in identifying
> the issue would be great.

Following I show the protocol on the client side related to the last step where
the NTLM type-3 message should be generated. Additionally I attach a
screenshot (proxy-side-protocol.png) of the protocol on the proxy side.

>>> Begin <<<
Text: Issue another request to this URL: ''
Text: Found bundle for host 0x2c21f38
Text: Re-using existing connection! (#0) with host
Text: Connected to ( port 9090 (#0)
Text: Curl_ntlm_create_type3_message: InitializeSecurityContext status=-2146893048
Text: Connection #0 to host left intact

libcurl message: Failure when receiving data from the peer
>>> End <<<

The function InitializeSecurityContext fails with an error (hexadecimal:
80090308) As far as I could find out this code corresponds to the error

The question is whether the proxy sent corrupted data (what I find quite
unlikely) or whether libcurl doesn't handle the received data as it should.

Any ideas, how to proceed to get this working?



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Received on 2014-09-05