[cifs-protocol] [REG:111051779565831] RE: dfs referral for sysvol and windows XP
hongweis at microsoft.com
Thu May 26 17:35:34 MDT 2011
I used your complete trace (dfs2.pcap) to see the entire scenario. The reason it falls back to NTLM from Kerberos is because it cannot get the TGS ticket for SPN (cifs/w2k8r2.home.matws.net). The error is KDC_ERR_S_PRINCIPAL_UNKNOWN. Have you checked if the SPN has been registered properly ?
339 3:34:02 PM 5/17/2011 24.0070710 XP ARES DFSC DFSC:Get DFS Referral Request, FileName: \w2k8r2.home.matws.net\sysvol, MaxReferralLevel: 4
340 3:34:02 PM 5/17/2011 24.0145370 ARES XP DFSC DFSC:Get DFS Referral Response, NumberOfReferrals: 2 VersionNumber: 4
488 3:34:22 PM 5/17/2011 43.8453860 XP ARES KerberosV5 KerberosV5:TGS Request Realm: W2K8R2.HOME.MATWS.NET Sname: cifs/w2k8r2.home.matws.net
489 3:34:22 PM 5/17/2011 43.8507430 ARES XP KerberosV5 KerberosV5:KRB_ERROR - KDC_ERR_S_PRINCIPAL_UNKNOWN (7)
As far as the DFS Referral version 4, I can see one thing that doesn't meet the requirement to be a version 4 of DFS referral. The TargetSetBoundary bit in ReferralEntryFlags of the first referral response entry MUST be set to 1, as per section 188.8.131.52 of MS-DFSC. In the both response entries returned from Samba , this bit is always 0.
- ReferralEntryFlags: 1024 (0x400)
unused1: (0000010000000...) - Unused
TargetSetBoundary: (.............0..) - The target corresponding to this referral entry is not the first target of a target set.
NameListReferral: (..............0.) - This is not a trusted domain or DC list referral
unused2: (...............0) - Unused
Please let me know what you think.
From: Matthieu Patou [mailto:mat at samba.org]
Sent: Sunday, May 22, 2011 3:52 PM
To: Hongwei Sun
Cc: pfif at tridgell.net; cifs-protocol at samba.org; MSSolve Case Email
Subject: Re: [REG:111051779565831] RE: [cifs-protocol] dfs referral for sysvol and windows XP
So the attached pcap show dfs referral traffic between a S4 and XP hosts.
Where we can see that XP is requesting a level 4 referral and that S4 answers to it with an answer following the specification.
After this XP is blocked or fallback to NTLM auth (not shown in this capture but in this one: http://www.matws.net/mat/misc/dfs2.pcap.gz).
So I'm wondering if it's normal, maybe XP didn't appreciate the level 4 answers.
On 19/05/2011 20:23, Hongwei Sun wrote:
> Hi, Matthieu,
> I need some clarification about your question. I have a problem to match the packets to what you have described. The trace has only 6 packets. The following are all the packets in the trace:
> 1 3:28:33 PM 5/17/2011 0.0000000 172.16.101.16 172.16.101.1 DFSC DFSC:Get DFS Referral Request, FileName:<empty>, MaxReferralLevel: 3
> 2 3:28:33 PM 5/17/2011 0.0001600 172.16.101.1 172.16.101.16 DFSC DFSC:Get DFS Referral Response, NumberOfReferrals: 2 VersionNumber: 3
> 3 3:28:33 PM 5/17/2011 0.1360020 172.16.101.16 172.16.101.1 DFSC DFSC:Get DFS Referral Request, FileName: \w2k8r2.home.matws.net, MaxReferralLevel: 3
> 4 3:28:33 PM 5/17/2011 0.1434180 172.16.101.1 172.16.101.16 DFSC DFSC:Get DFS Referral Response, NumberOfReferrals: 1 VersionNumber: 3
> 5 3:28:33 PM 5/17/2011 0.1440790 172.16.101.16 172.16.101.1 DFSC DFSC:Get DFS Referral Request, FileName: \w2k8r2.home.matws.net\sysvol, MaxReferralLevel: 4
> 6 3:28:33 PM 5/17/2011 0.1514540 172.16.101.1 172.16.101.16 DFSC DFSC:Get DFS Referral Response, NumberOfReferrals: 2 VersionNumber: 4
> Could you explain more about the configuration of your testing , scenario as well as the behavior in question? It will be better if you can point out the packets in question.
> -----Original Message-----
> From: cifs-protocol-bounces at cifs.org
> [mailto:cifs-protocol-bounces at cifs.org] On Behalf Of Matthieu Patou
> Sent: Tuesday, May 17, 2011 4:09 PM
> To: Interoperability Documentation Help; pfif at tridgell.net;
> cifs-protocol at samba.org
> Subject: [cifs-protocol] dfs referral for sysvol and windows XP
> Hello doc help,
> While revisiting the DFS implementation for samba I remade some tests with XP and It seems that when doing the last step in order to resolve \\domain.tld\sysvol.
> Even if we tend to send the same frame, XP comes to samba 4 when asking for a DC holding \\domain.tld\sysvol. So as we support this level we return entry for this level.
> But then it fails to connect to \\dc.domain.tld\sysvol and keep doing ntlm connection to \\domain.tld\sysvol.
> Is this "normal" ?
> I put another capture here: http://www.matws.net/mat/misc/dfs2.pcap.gz
> where we can clearly see that the client starts to do NTLM auth to connect to \\domain.tld.
> Thanks for your answers.
> Matthieu Patou
> Samba Team http://samba.org
> Private repo http://git.samba.org/?p=mat/samba.git;a=summary
Samba Team http://samba.org
Private repo http://git.samba.org/?p=mat/samba.git;a=summary
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