SMBv2 and Windows 7

Question

After disabling SMBv1 through some Firewalls within my network, I'm encountering a problem between a nas and the windows 7 workstations.

C:\Users\Username>net use * \\NAS.FQDN\SHARENAME
System error 64 has occurred.

The specified network name is no longer available.

SMBv1 is properly disabled onto the client [SC] QueryServiceConfig SUCCESS

    SERVICE_NAME: lanmanworkstation
            TYPE               : 20  WIN32_SHARE_PROCESS
            START_TYPE         : 2   AUTO_START
            ERROR_CONTROL      : 1   NORMAL
            BINARY_PATH_NAME   : C:\Windows\System32\svchost.exe -k NetworkService
            LOAD_ORDER_GROUP   : NetworkProvider
            TAG                : 0
            DISPLAY_NAME       : Workstation
            DEPENDENCIES       : Bowser
                               : MRxSmb20
                               : NSI
            SERVICE_START_NAME : NT AUTHORITY\NetworkService

But my firewall and wireshark just shows SMB and no SMB2 protocol.

Is windows 7 encapsulating SMBv1 and SMBv2 using the same header ?

I've checked with both IP and FQDN, nothing is working, I tried by disabling netbios over TCP/IP, results are always the same.

In order to get this working, dropping the FW rule for SMBv1 is the only solution ? Or is there any update to change this behavior on win7 ?

The model is an EMC VNX 5400. SMBv2 is up and running on it. — Wheatstone, Oct 11 '17 at 15:32

bjoster · Accepted Answer · 2017-10-13T13:51:40.190

7

SMB protocol handshake is always SMB, for backwards compatibility. The connection is upgraded later on. If you deny all packets with SMB headers, no connection will be established.

You cann see this in a successful protocol negotiation:

edited Oct 13 '17 at 13:51

answered Oct 11 '17 at 15:38

bjoster

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SMBv2 and Windows 7

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