Forum Discussion
W10-1903 UNC path failing 0x80070043
Hi everyone. We got access to the Dell KB and see the issue in Dell/EMCs 'Unity' CIFS implementation.
From the DELL EMC KB attached to thread (below), the Unity SMB Server implementation is failing on the "SMB2_NETNAME_CONTEXT" and "SMB2_COMPRESSION_CAPABILITIES" we added in 1903. These were changes designed to add some new capabilities to SMB; we make some variant of these at most OS releases. If an SMB/CIFS server doesn't recognize capabilities, it should ignore them, not fail. Otherwise Dell would have to update their SMB implementation every time we released a new SMB capability that didn't also include a protocol dialect revision (like "SMB 3.1.2"), forever and ever.
Error Messages in the Unity c4_safe_ktrace.log:
sade:SMB: 3:[nas_serverx] Unrecognized SMB2 negotiate context type 0003
sade:SMB: 3:[nas_serverx] Unrecognized SMB2 negotiate context type 0003SMB client sends the compression context before the netname context, so the server encounters the compression context first. The Unity server would probably encounter the same problem with the netname context. Instead of failing when their SMB Server version doesn't support more advanced capabilities, it should be ignoring those capabilities. This is what Windows and other 3rd party SMB products do.
kurgan thanks for opening this techcommunity item, I'm sorry I didn't see it until now.
Ned Pyle | Principal Program Manager, MS | @nerdpyle on twitter
itkpli Same problem also here with Build 19h1 and Dell compellent FluidFS. no poblem with windows servers. does anyone else can test on a linux machine with standard samba ?
Not sure why most people are trying to blame EMC / FluidFS for the SMB implementation.
I think Microsoft should be the one to fix the issue.
SMB 3.1.1 is not new, our EMC NAS has been on SMB 3.1.1 for years, and on previous Windows 10 releases (1703, 1709, 1803, 1809), it is able using SMB 3.1.1 to connect to our EMC NAS servers. Why the same SMB 3.1.1 stopped working in 1903?
Try to have a Windows 10 PC with build of (1703, 1709, 1803, 1809) connected with your EMC NAS. and run Get-SMBConnection, it should prove that the connection is utilizing SMB 3.1.1. There is no issue on EMC's SMB implementation.
IronRolia Because Dell was not following the SMB specification. An SMB server is not supposed to fail when sent unsupported capabilities during NEGOTIATE phase, regardless of the maximum dialect support. 1903 added a Compression flag to SMB capabilities (which was also publicly documented so that vendors could support it if they wished) and if not supporting compression, the Dell device is supposed to respond that it doesn't support that flag, not error and tear down session.
This is why Dell already fixed their other product with this symptom. Other manufacturers were unaffected by the addition of SMB Compression support in 1903 because they followed the spec.
Note: I own SMB and its specification.
Thanks for the reply.
My question is if DELL did not follow the SMB specification, how would the SMB 3.1.1 dialect / protocol worked on previous Windows 10 releases with EMC NAS?
If I run GET-SMBConnection when connected to our EMC NAS, on previous Windows 10 releases, it clearly shows the connection are utilization SMB 3.1.1 protocol.
Do you have prove of any other vendors that actually use SMB 3.1.1 on their NAS storage that work with Windows 10 1903?
Are you suggesting that Microsoft also did not follow the SMB specs on their previous Win 10 releases, and now they decided to "fix" it in release 1903?
I really hope Microsoft and DELL can work together to investigate the issue collaboratively and have this issue fixed.
itkpliwhat did Dell say?
Did anyone fix this issue yet? we are on the same boat with Dell Unity, we will also open a case with Dell. Just want to know if anyone has any insights.
ThiagoCardosoThe response from Dell/EMC so far has been to tell us to contact Microsoft.
While it might be an issue with Windows 10 1903 it's still something Dell/EMC should be concerned about because it will hurt their customers. I'll update here if I get any more info.
- If you'll shoot me the case number, I'll include it in a ticket that I create with them.
