NAS SMB server not accepting packets > 65k size. Does SMB2->Negotiate_Protocol_Response->Max_Write_Size = 65536 Matters?

[Saji VR]

>1. Can server accept/send more than 65K sized packet, if
>SMB2->Negotiate_Protocol_Response->Max_Write_Size = 65536, Max_Read_Size
>= 65536?

That dictates the max read/write size supported by server, client is expected to honor that. So answer is No. NetApp filer does not support reads/write larger than 64K

>2. If SMB-server sends STATUS_NOT_SUPPORTED for
>FSCTL_VALIDATE_NEGOTIATE_INFO, Is it expected to carry the transaction
>further?

Yes, Only requirement is the response has to be signed, which assures that the response is coming from the server itself.

On 4/30/17, 8:25 AM, "samba-technical on behalf of amit kumar via samba-technical" <samba-technical-bounces at lists.samba.org on behalf of samba-technical at lists.samba.org> wrote:

    Hello,
    
    This is situation:
    
    *    [netApps SMB-server]                     [RHEL-7.1-Client]*
                    |      =SMB 2/3=                           |
                    |                                          sending
    data>65k Fail
                    |                                          sending
    data<65k Passes 
    Max Write/Read Size[65535]                                               
    
    *From Packet Captures*:
    1. For FSCTL_VALIDATE_NEGOTIATE_INFO message:
    NAS returned STATUS_NOT_SUPPORTED & RHEL client drops the transaction.
    
    Though these are filters on NAS Server:
    
    NAS_Server::*> vserver cifs options show 
                               ...
    Max Buffer Size for SMB1 Message: 65535
    	            SMB2 Enabled: true
                        SMB3 Enabled: true
                        WINS Servers: 
    
    
    2. SMB2->Negotiate_Protocol_Response->Max_Write_Size = 65536,
    Max_Read_Size = 65536
    	*[Windows SMB-server]                     [RHEL-7.1-Client]*
                    |      =SMB 2/3=                           |
                    |                                       sending data>65k
    Passes   Max Write/Read Size[8388608]                                
                    
    
    
    *From Packet Captures*:
    1. For FSCTL_VALIDATE_NEGOTIATE_INFO message:
    Win12 returned STATUS_SUCCESS
    
    
    
    
    
    
    
    
    
    
    
    
    2. SMB2->Negotiate_Protocol_Response->Max_Write_Size = 8388608,
    Max_Read_Size = 8388608
    	*        **[RHEL SMB-server]                     [RHEL-7.1-Client]*
                    |      =SMB 2/3=                           |
                    |                                       sending data>65k
    Passes     
    Max Write/Read Size[8388608]
    
    
    *From Packet Captures*:
    1. For FSCTL_VALIDATE_NEGOTIATE_INFO message:
    RHEL returned STATUS_SUCCESS
    
    
    
    
    
    
    
    
    
    
    
    
    2. SMB2->Negotiate_Protocol_Response->Max_Write_Size = 8388608,
    Max_Read_Size = 8388608
    
    
    My queries:
    1. Can server accept/send more than 65K sized packet, if
    SMB2->Negotiate_Protocol_Response->Max_Write_Size = 65536, Max_Read_Size
    = 65536?
        Again, on NAS, On cifs-mounted shares packets > 65k succeed to get
    transferred..
    2. If SMB-server sends STATUS_NOT_SUPPORTED for
    FSCTL_VALIDATE_NEGOTIATE_INFO, Is it expected to carry the transaction
    further?
    
    -- 
    Thanks
    Amit Kumar
    !!If you stumble, get back up. 
    What happened yesterday, no longer matters.
    Today is another day to move closer to your GOAL!!