[Samba] Windows clients connecting to SMB share differently over IP than DNS

Jeremy Allison jra at samba.org
Thu Apr 1 16:50:12 UTC 2021


On Thu, Apr 01, 2021 at 09:44:40AM -0700, Gavin Greenwalt via samba wrote:
>I have a CIFS share on a samba server ((Version 4.4.16)) joined as a member
>to a Windows 2012 R2 AD domain. If I on a windows 10 machine mount the
>share over IP address it takes about 14.5 minutes for 21,000 files to copy.
>(which is in of itself slow but I believe due to a lack of official SMB3
>multichannel support in Samba.) If I mount the share with the DNS name it
>takes *205* minutes to copy the 21,000 files to copy.  More than 10x
>slower.
>
>Connecting to the IP address (e.g. \\1.1.1.1\share) the SMB transaction
>goes as expected.
>
>5153       19.122016            2.2.2.2   1.1.1.1   Create Request File:
>temp\Folder\1 - Copy (83).txt
>
>5154       19.122612            1.1.1.1   2.2.2.2   Create Response File:
>temp\Folder\1 - Copy (83).txt
>
>5155       19.122716            2.2.2.2   1.1.1.1   SetInfo Request
>FILE_INFO/SMB2_FILE_ENDOFFILE_INFO File: temp\Folder\1 - Copy (83).txt
>
>5156       19.122886            1.1.1.1   2.2.2.2   SetInfo Response
>
>5157       19.122951            2.2.2.2   1.1.1.1   Write Request Len:8888
>Off:0 File: temp\Folder\1 - Copy (83).txt
>
>5159       19.123135            1.1.1.1   2.2.2.2   Write Response
>
>5160       19.123165            2.2.2.2   1.1.1.1   SetInfo Request
>FILE_INFO/SMB2_FILE_BASIC_INFO File: temp\Folder\1 - Copy (83).txt
>
>5161       19.123308            1.1.1.1   2.2.2.2   SetInfo Response
>
>5162       19.123338            2.2.2.2   1.1.1.1   GetInfo Request
>FILE_INFO/SMB2_FILE_NETWORK_OPEN_INFO File: temp\Folder\1 - Copy (83).txt
>
>5163       19.123420            1.1.1.1   2.2.2.2   GetInfo Response
>
>5164       19.123541            2.2.2.2   1.1.1.1   GetInfo Request
>FILE_INFO/SMB2_FILE_NETWORK_OPEN_INFO File: temp\Folder\1 - Copy (83).txt
>
>5165       19.123616            1.1.1.1   2.2.2.2   GetInfo Response
>
>5166       19.123666            2.2.2.2   1.1.1.1   GetInfo Request
>SEC_INFO/SMB2_SEC_INFO_00 File: temp\Folder\1 - Copy (83).txt
>
>5167       19.127104            1.1.1.1   2.2.2.2   GetInfo Response,
>Error: STATUS_BUFFER_TOO_SMALL
>
>5168       19.127171            2.2.2.2   1.1.1.1   GetInfo Request
>SEC_INFO/SMB2_SEC_INFO_00 File: temp\Folder\1 - Copy (83).txt
>
>5169       19.130321            1.1.1.1   2.2.2.2   GetInfo Response
>
>5170       19.130584            2.2.2.2   1.1.1.1   Close Request File:
>temp\Folder\1 - Copy (83).txt
>
>5171       19.130800            1.1.1.1   2.2.2.2   Close Response
>
>
>
>Over DNS (e.g. \\server\share) things screech to a halt and follow a
>completely different transaction loop involving a tree connect request over
>every single file.  This slows things down to about 1 file/second.
>
>
>
>4365       9.064473              2.2.2.2   1.1.1.1   Session Setup Request
>
>4367       9.067749              2.2.2.2   1.1.1.1   Create Request File:
>temp\Folder\1 - Copy (83).txt
>
>4749       10.061721            2.2.2.2   1.1.1.1   Create Request File:
>temp\Folder
>
>4755       10.068555            1.1.1.1   2.2.2.2   Session Setup Response
>
>4756       10.068922            2.2.2.2   1.1.1.1   Tree Connect Request
>Tree: \\Synology\Share
>
>4757       10.069262            1.1.1.1   2.2.2.2   Create Response File:
>temp\Folder\1 - Copy (83).txt
>
>4758       10.069483            2.2.2.2   1.1.1.1   SetInfo Request
>FILE_INFO/SMB2_FILE_ENDOFFILE_INFO File: temp\Folder\1 - Copy (83).txt
>
>4759       10.069613            1.1.1.1   2.2.2.2   Create Response File:
>temp\Folder
>
>4760       10.069729            2.2.2.2   1.1.1.1   Find Request File:
>temp\Folder SMB2_FIND_ID_BOTH_DIRECTORY_INFO Pattern: *;Find Request File:
>temp\Folder SMB2_FIND_ID_BOTH_DIRECTORY_INFO Pattern: *
>
>4762       10.074482            1.1.1.1   2.2.2.2   Tree Connect Response,
>Error: STATUS_ACCESS_DENIED
>
>4763       10.074550            2.2.2.2   1.1.1.1   Session Logoff Request
>
>4764       10.074688            1.1.1.1   2.2.2.2   SetInfo Response
>
>4765       10.074810            2.2.2.2   1.1.1.1   Write Request Len:8888
>Off:0 File: temp\Folder\1 - Copy (83).txt
>
>4767       10.077222            1.1.1.1   2.2.2.2   Response;Find Response,
>Error: STATUS_NO_MORE_FILES
>
>4769       10.077405            1.1.1.1   2.2.2.2   Session Logoff Response
>
>4770       10.077448            2.2.2.2   1.1.1.1   Close Request File:
>temp\Folder
>
>4771       10.077535            1.1.1.1   2.2.2.2   Write Response
>
>4772       10.077630            1.1.1.1   2.2.2.2   Close Response
>
>4774       10.077712            2.2.2.2   1.1.1.1   SetInfo Request
>FILE_INFO/SMB2_FILE_BASIC_INFO File: temp\Folder\1 - Copy (83).txt
>
>4775       10.077872            2.2.2.2   1.1.1.1   Create Request File:
>temp\Folder
>
>4776       10.078096            1.1.1.1   2.2.2.2   SetInfo Response
>
>4777       10.078166            2.2.2.2   1.1.1.1   GetInfo Request
>FILE_INFO/SMB2_FILE_NETWORK_OPEN_INFO File: temp\Folder\1 - Copy (83).txt
>
>4778       10.078337            1.1.1.1   2.2.2.2   Create Response File:
>temp\Folder
>
>4779       10.078378            1.1.1.1   2.2.2.2   GetInfo Response
>
>4781       10.078430            2.2.2.2   1.1.1.1   Close Request File:
>temp\Folder
>
>4782       10.078550            1.1.1.1   2.2.2.2   Close Response
>
>4783       10.078648            2.2.2.2   1.1.1.1   GetInfo Request
>FILE_INFO/SMB2_FILE_NETWORK_OPEN_INFO File: temp\Folder\1 - Copy (83).txt
>
>4784       10.078670            2.2.2.2   1.1.1.1   Create Request File:
>temp
>
>4785       10.078748            1.1.1.1   2.2.2.2   GetInfo Response
>
>4786       10.078821            2.2.2.2   1.1.1.1   GetInfo Request
>SEC_INFO/SMB2_SEC_INFO_00 File: temp\Folder\1 - Copy (83).txt
>
>4787       10.078897            1.1.1.1   2.2.2.2   Create Response File:
>temp
>
>4788       10.078998            2.2.2.2   1.1.1.1   Close Request File: temp
>
>4789       10.083060            1.1.1.1   2.2.2.2   GetInfo Response,
>Error: STATUS_BUFFER_TOO_SMALL
>
>4790       10.083148            1.1.1.1   2.2.2.2   Close Response
>
>4791       10.083155            2.2.2.2   1.1.1.1   GetInfo Request
>SEC_INFO/SMB2_SEC_INFO_00 File: temp\Folder\1 - Copy (83).txt
>
>4792       10.083252            2.2.2.2   1.1.1.1   Create Request File:
>
>4793       10.087615            1.1.1.1   2.2.2.2   GetInfo Response
>
>4794       10.087860            1.1.1.1   2.2.2.2   Create Response File:
>
>4796       10.087948            2.2.2.2   1.1.1.1   Find Request File:
>SMB2_FIND_ID_BOTH_DIRECTORY_INFO Pattern: *;Find Request File:
>SMB2_FIND_ID_BOTH_DIRECTORY_INFO Pattern: *
>
>4797       10.088101            2.2.2.2   1.1.1.1   Close Request File:
>temp\Folder\1 - Copy (83).txt
>
>4798       10.089075            1.1.1.1   2.2.2.2   Find Response;Find
>Response, Error: STATUS_NO_MORE_FILES
>
>4800       10.089169            2.2.2.2   1.1.1.1   Close Request File:
>
>4801       10.089291            1.1.1.1   2.2.2.2   Close Response
>
>4802       10.089375            1.1.1.1   2.2.2.2   Close Response
>
>
>
>The initial delay seems to be somewhat random. E.g. but consistenly around
>1second per file for the negotiation.
>
>11686    28.24ms               2.2.2.2   1.1.1.1   Session Setup Request
>
>11688    28.24ms               2.2.2.2   1.1.1.1   Create Request File:
>temp\Folder\1 - Copy (114).txt
>
>11997    28.74ms               2.2.2.2   1.1.1.1  Create Request File:
>temp\Folder\Files
>
>12079    28.99ms               1.1.1.1   2.2.2.2   Session Setup Response
>
>12080    28.99ms               2.2.2.2   1.1.1.1   Tree Connect Request
>Tree: \\Synology\Share
>
>Do windows clients connect to \\path\shares differently from
>\\ip.ad.d.ress\paths? I’m kind of stuck trying to think of what else to
>test to make progress on why the server is so much slower on Windows 10
>clients when mapped over DNS name.   Windows reports the smb connection as
>a 3.1.1 dialect for both \\ip and \\dns.
>
>The only intriguing thing I can note is that Windows connects to the \\ip
>address as domain\user for credentials. However no matter what I do it
>connects as domain*.com*\user for named server connections (both Windows
>and Linux\samba).  For comparison a Windows 2012R2 file server and a
>Windows 10 desktop client follow the correct (fast\streamlined) SMB
>transaction with both DNS and IP Address.  So it seems to be limited to the
>Samba share.

That's... really bizarre. The only difference between IP address
and dns name should be in the auth used. For IP it's going to
be NTLMv2, for DNS it could be krb5.



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