Re: [squid-users] got NTLMSSP command 3, expected 1

From: Nick Cairncross <Nick.Cairncross_at_condenast.co.uk>
Date: Mon, 4 Oct 2010 10:26:49 +0100

>On Mon, Oct 4, 2010 at 9:44 AM, Nick Cairncross
><Nick.Cairncross_at_condenast.co.uk> wrote:
>> On 04/10/2010 07:48, "guest01" <guest01_at_gmail.com> wrote:
>>
>>>got NTLMSSP command 3, expected 1
>>
>> As you say isn't that because a Kerberos client is trying to send auth
>>and
>> thus not capable of NTLM? Can you track it down to the requesting
>> machine(s) and client? It's like my Mac Safaris can only use NTLM and
>>not
>> Kerberos, only reverse.. I use both helpers. Kerberos auth ordered first
>> and then NTLM second in squid conf.
>>
>> N
>>
>yes, at least the error messages suggests that a client wants to send
>kerberos specific data, but squid expected ntlm. But I don't know why,
>because in general everything is working. But sometimes it is not,
>then the user will get a browser pop-up asking for credentials (which
>should not happen either with kerberos or ntlm). A few seconds later
>it is working again (normally pressing escape a couple of times is
>enough and then the user is authenticated again by ntlm).
>
>I tried to figure out which browser caused that problem, in my case it
>was FF 3.6.10, but if I remember correctly, then I had the same
>problem with IE too.
>
>But you are right, if I am using both helpers (ntlm, kerberos) it
>should not appear, right? So the only working solution is to use
>kerberos too? Any other possible fixes?
>

Is the example you are talking about from within Firefox or IE7+? I see
the same thing for my non-domain joined machines in Firefox. FF tries
Kerberos first and then changes to NTLM on pressing escape. Since they
can't get a ticket for a non domain machine my users need to use NTLM as a
backup - your cache.log might show something like:

2010/10/04 10:09:53| authenticateAuthenticate: Unexpected change of
authentication scheme from 'negotiate' to 'NTLM
TlRMTVNTUAABAAAAB4IIogAAAAAAAAAAAAAAAAAAAAAGAbAdAAAADw==' (client
192.168.1.27)

(In Firefox) For me if I press escape I then receive a *slightly*
different prompt relating to squid auth. I then enter my ntlm creds
(domain\username) and I'm on. Logs show the user account is NTLM auth and
not Kerberos. If it WAS a domain joined machine it would be the Kerberos
UPN I would see from the start

In IE if you disabled 'Integrated Windows Authentication' in the settings
then I would be able to use NTLM for my non-domain machines as IE wants to
use Kerberos otherwise.

As for a 'fix', there isn't one AFAIK. However, some things to think
about: is there a delay somewhere relating relating to NTLM auth?
Sometimes not enough helpers, latency, locked accounts, bad lookups/DNS.

As yet there is no wrapper for both Kerberos and NTLM, so two helpers it
is.

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Received on Mon Oct 04 2010 - 09:26:56 MDT

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