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
We're seeing the same thing - this issue seems to have returned sometime this year. Setting Fluid FS to the below seems to have stabilized the issue, at the cost of downgrading to SMB2.
Frame 448: 131 bytes on wire (1048 bits), 131 bytes captured (1048 bits) on interface \Device\NPF_{[redacted]}, id 0
Ethernet II, Src: [redacted] ([redacted], Dst: VMware_[redacted] ([redacted])
Internet Protocol Version 4, Src: [redacted], Dst: [redacted]
Transmission Control Protocol, Src Port: 445, Dst Port: 55205, Seq: 1, Ack: 273, Len: 77
NetBIOS Session Service
SMB2 (Server Message Block Protocol version 2)
SMB2 Header
ProtocolId: 0xfe534d42
Header Length: 64
Credit Charge: 0
NT Status: STATUS_INVALID_PARAMETER (0xc000000d)
Command: Negotiate Protocol (0)
Credits granted: 17
Flags: 0x00000001, Response
Chain Offset: 0x00000000
Message ID: 0
Process Id: 0x0000feff
Tree Id: 0x00000000
Session Id: 0x0000000000000000
Signature: 00000000000000000000000000000000
[Response to: 446]
[Time from request: 0.000216000 seconds]
Negotiate Protocol Response (0x00)
[Preauth Hash: [redacted]…]
StructureSize: 0x0009
Error Context Count: 0
Reserved: 0x00
Byte Count: 0
Error Data: 34
I'm betting Dell's "fix" was just to once again hard-code the new values and not use the dynamic behavior Ned mentioned above. Hopefully they will issue a new patch.
MikeCrowley They released an update to fix this just recently. We applied it over the weekend and it appears to have resolved the SMB 3.1.1 issues.