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RE: Error in proxy connection

From: Ranu Gontia <>
Date: Wed, 11 Feb 2009 14:40:14 +0530

-----Original Message-----
[] On Behalf Of Daniel Stenberg
Sent: Wednesday, February 11, 2009 2:18 PM
To: libcurl development
Subject: RE: Error in proxy connection

On Wed, 11 Feb 2009, Ranu Gontia wrote:

>>> < HTTP/1.1 407 Proxy Authentication Required ( The ISA Server requires
>>> authoriza
>>> < Proxy-Authenticate: Negotiate
>>> < Proxy-Authenticate: Kerberos
>>> < Proxy-Authenticate: NTLM


>> curl_easy_setopt(curlhandle, CURLOPT_PROXYAUTH, CURLAUTH_BASIC);

> The proxy says it wants Negotiate, Kerberos or NTLM authentication. You
> explicitly tell libcurl to use Basic. I doubt you'll win.

>> If I specify that I am using proxy tunnel
>> i.e. curl_easy_setopt(curlhandle, CURLOPT_HTTPPROXYTUNNEL, 1);
>> then following error comes -:

> But why are you using CURLOPT_HTTPPROXYTUNNEL? Do you even understand what
> does? The 502 proxy response should be a hint you're not allowed to tunnel

> through the proxy to port 21 on the "outside".

I have tried all the combination. Changed " curl_easy_setopt(curlhandle,
CURLOPT_PROXYAUTH, CURLAUTH_NTLM);" still got the same error.

I have a cooperate proxy which is ISA server and any request has to pass
through the same. Only authenticated users are allowed.

If I try to do the same with my browser it allows. But not through lib curl.

Received on 2009-02-11