Forum Discussion
W10-1903 UNC path failing 0x80070043
I can no longer access network shares through unc paths \\server\share I get the 0x80070043 "Network name cannot be found" error.
I suspect that this is related to the removal of Homegroups? but surely it was not intended to break basic UNC functionality, or am I missing something?
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
- NedPyle
Microsoft
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
NedPyle Hi Ned,
thanks for looking into this. The other Dell product, FluidFS, has the same issue. One of my colleagues spotted the new compression header using tcpdump when looking into this issue with the preview release of 1903 in April. We opened a case with Dell on the 30th April and we were told there wouldn't be any changes to FluidFS and we should open a case with Microsoft. Unfortunately we don't have a support agreement with Microsoft so just left feedback for the 1903 preview.
I haven't had any updates from Dell for a while so I'm not sure if they are looking at changing FluidFS, but now I have confirmation from you I can escalate it.
Thanks again.
Just a quick update on this - I have had confirmation from Dell that they are working on a fix for FluidFS.
Good news, everyone!
Dell/EMC has a work around for this issue. By setting the SMB Max Protocol version to 3.0.2 (down from 3.1.1) I am able to access shares again. Please start a Dell/EMC support ticket and quote SR 14282798.
Kudos to engineer Harsha Vardan for providing the work around!
dwatsonI got the same info yesterday as well from a local EMC representative who had looked at your SR and it's good that they have a workaround.
However there are quite a lot of improvements in 3.1.1 compared to 3.02.
More info: What’s new in SMB 3.1.1 in the Windows Server 2016 Technical Preview 2
dwatson Presumably this fix is for Unity?
We still have the same problem with FluidFS and Dell have told us it is Microsoft's problem.
Has anybody found a fix for FluidFS?
Just answering my own question - it looks like completely disabling SMBv3 on FluidFS is a workaround. Not great, but at least it gets things working again.
update,:
it seems it may be specific to Dell Compellent Fluidity, so probably some sort of issue with their smb implementation.
It works fine with my home Synology Nas, and MS fileserversBut it has worked fine on previous win 10 versions
kurgan Any luck figuring this out? Having the same problem over here with our Dell EMC UNITY SAN and it's killing me.
It works for me now, not sure if it is a windows update or update on fluidity that has fixed it.
- Make sure they are connected on the same network. In network sharing settings, enable 128 Bit encryption and allow network discovery. There are 7 services related to network sharing in services.msc. Also, both systems must run on the same build of Windows 10.
I think you're missing a part of this. We're talking about a DELL EMC box not running Windows. It's running Linux but SMB has worked without issue on all prior Windows 10 versions. Things broke with 1903
Just downloaded and installed the Windows 10 Enterprise 1903 release from MSDN to test and this issue is still present. On latest build 18362.53. Our company's files shares are mostly hosted from Dell EMC/Unity. I have been able to confirm that Windows Server file shares and Nutanix Files shares are unaffected. Hopefully they will get this fixed by the RTM next month.
- Any updates on this? Thanks
Dell EMC just released an official KB about this:
They still recommend to downgrade to 3.0.2 or to go back to 1809 on the clients but it says that they are investigating an enchancement to adress this issue.
- I think it's only possible to downgrade to 3.0.2 if your running on a Unity platform.
There is instructions provided for Unity in this kb: DTA 534173For Compellent; it seems like you have to disable v3.
