Symptoms

File OE Upgrade to 7.1.82.0After upgrade to File OE 7.1.82.0 access to CIFS/SMB shares is lost a short time after DM is rebooted with the new DART version.CIFS server domain is a single label domain, i.e. the domain doesn't have a prefix/suffix and no dot in domain name.server_log shows these log errors:2018-06-28 13:58:52: SMB: 4: Unsupported authentication mode: authMethod:4, kerberosSupport:1, negoMethod:02018-06-28 13:58:52: SMB: 3: OpenAndBind[NETLOGON] DC=DC2 failed: Bind_OpenXFailed DOMAIN_CONTROLLER_NOT_FOUND2018-06-28 13:58:52: SMB: 3: Can't open NETLOGON file for DC=DC12018-06-28 13:58:52: SMB: 6: DC0x01bce32808: setDCDown DC, refresh if needed (origin=netLogonAuth2)2018-06-28 13:58:52: SMB: 6: DC*DC1(192.168.xx.xx) R=331 T=0 ms S=17,0xc0000233/272018-06-28 13:58:52: SMB: 3: W2KDCRequestB:setDCDown(DC1)2018-06-28 13:58:52: SMB: 4: Cannot get kerberos TGT for 'user1.mydomain' with user 'mydomain\cifsserver$': No '.' found in the user domain name2018-06-28 13:58:52: SMB: 4: Cannot get kerberos TGT for 'user2.mydomain' with user 'mydomain\cifsserver$': No '.' found in the user domain name2018-06-28 13:58:52: SMB: 4: Cannot get kerberos TGT for 'user3.mydomain' with user 'mydomain\cifsserver$': No '.' found in the user domain nameAccess is working for a short time after DM reboot, although slow and sluggish.Additional Symptoms:- pdc dump returned i/o error----------------- pdc dump ------------------------------xxxxx : commands processed: 0Error 4020: xxxxx: Input/output errorTimed outcifsThrd command showed a lot of blocked cifs threads:----------------- cifsThrd ------------------------------tjure-dm1 : commands processed: 1command(s) succeededoutput is complete1530176768: SMB: 6: cifsThrd: checking blocked threadsminimum: 0/384 threads, 5 seconds1530176768: SMB: 3: List of blocked threads1530176768: SMB: 3: 2SMB003 BLOCKED for 58 seconds in SessionSetup2SMB003 at 0x000e5ecd60: WaitingMutex at 0x005eb83d80 (malloc heap)ctx=[0x0007a6e808-0x0007a6eb10] Client=xxxDC=[0x0007dfb008-0x0007dfb260] SVEN1530176768: SMB: 3: 2SMB004 BLOCKED for 42 seconds in SessionSetup2SMB004 at 0x000e5ed0b0: WaitingMutex at 0x005eb83d80 (malloc heap)ctx=[0x005ea58008-0x005ea58310] Client=xxxxC=[0x0007dfb008-0x0007dfb260] SVEN1530176768: SMB: 3: 2SMB005 BLOCKED for 34 seconds in SessionSetup2SMB005 at 0x000e5ed400: WaitingMutex at 0x005eb96180 (malloc heap)-----------------------------------------------------------------------Customer is using a single label domain "dc-domain":CIFS Server XXXX[DC-DOMAIN] RC=1442Full computer name=XXXX-domain realm=DC-DOMAIN Comment='EMC-SNAS:T7.1.83.2'if=tjure01 l=192.168.xx.xxx b=192.168.xx.xxx mac=0:xx:xx:xxx:xx:xxFQDN=XXXX.dc-domain (Updated to DNS)Password change interval: 0 minutesLast password change: Thu Jun 28 07:23:39 2018 GMTPassword versions: 2

Cause

The 7.1.82.0 release enables the use of Server Message Block version 2 (SMB2) as the dialect for secure channel communications between the VNX CIFS server and the Active Directory domain controller.There's a code issue with SMBv2 DC communication and single label domains.

Resolution

If your CIFS server is joined to a single label domain and you experience this issue after upgrade to File OE 7.1.82.0, there is a workaround or a hotfix available.The hotfix is based on File OE Release 7.1.83.2.Please contact Dell EMC Technical Support or your Authorized Service Representative, and quote this Knowledgebase article ID.

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