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SMB2 windows 2012 issue in mapping a drive RRS feed

  • Question

  • Hello,

    I am facing a problem with smb2 access when windows 2012 server is used as client. 

    Let me explain my setup details and the problem. I have a linux based smb server which support  SMB2 protocol and I am using Windows 2012 as the smb client.  My smb server listens only on port 139 not on port 445. First I map a drive on my windows 2012 server from smb server. In packet trace I can see that WIN2012 first try tcp connection to port 445, then to 139 and mapping succeeds. Now I restart my smb service and I can see that server is sending TCP reset for the connection on 139. After service smb service restart, I click on the mapped drive to reconnect but it fails. In packet trace I can see that client try connecting to port 445, server respond with TCP reset, now client is not trying to connect to port 139 and hence reconnecting fails.

    I dont see this issue when I use SMB1 in WIN2012 or even SMB2 in WIN7. ie I am seeing this issue only with SMB2 client in WIN2012. Could you please help me in understanding this behavior of windows 2012. 

    Thanks

    Tomy

    Monday, February 2, 2015 11:15 AM

Answers

  • Updating thread [ Closing notes ] :

    The behavior observed with windows 2012 is by-design. In windows 8 and 8.1 , the first connection can end up going out over TCP/139, but once SMB2 is negotiated, we will only use TCP/445. Hence, starting windows 8 and 8.1; smb2 will reliably work only on TCP/445.

    With windows 10, TCP/139 is deprecated and even your first connection will not be successful. Our recommendation is to support SMB2 on port 445.

     

    Tarun Chopra | Escalation Engineer | Open Specifications Support Team

    Friday, February 6, 2015 5:39 PM

All replies

  • Hello Tomy -

    Thank you for contacting Microsoft Support.

    I'll be helping you with this inquiry and request to send SMB2 (!smb1) network traces for win7-yourServer and windows2012-yourServer to my attention 'Tarun' at dochelp @ Microsoft dot com.

    Thanks. 


    Tarun Chopra | Escalation Engineer | Open Specifications Support Team

    Monday, February 2, 2015 5:39 PM
  • Hello Tarun,

    I have sent a mail with the required packet traces.

    Thanks

    Tomy

    Tuesday, February 3, 2015 10:18 AM
  • Thanks Tomy. Let's work thro' dochelp and we will circle back to post our findings. 

    Tarun Chopra | Escalation Engineer | Open Specifications Support Team

    Tuesday, February 3, 2015 5:09 PM
  • Updating thread [ Closing notes ] :

    The behavior observed with windows 2012 is by-design. In windows 8 and 8.1 , the first connection can end up going out over TCP/139, but once SMB2 is negotiated, we will only use TCP/445. Hence, starting windows 8 and 8.1; smb2 will reliably work only on TCP/445.

    With windows 10, TCP/139 is deprecated and even your first connection will not be successful. Our recommendation is to support SMB2 on port 445.

     

    Tarun Chopra | Escalation Engineer | Open Specifications Support Team

    Friday, February 6, 2015 5:39 PM