[Samba] multiple smb commands (some non AndX) in one packet

Shirish Pargaonkar shirishpargaonkar at gmail.com
Wed Jun 4 20:28:31 GMT 2008

You mean 4-byte header FF 53 4D 42?
In another recreate, tcp frame has two smb requests,
close (0x4) and locking andx (0x24) each with this four byte header.

On 6/4/08, Volker Lendecke <Volker.Lendecke at sernet.de> wrote:
> On Wed, Jun 04, 2008 at 02:20:45PM -0500, Shirish Pargaonkar wrote:
> > No, I am talking about multiple smb commands in the same tcp frame and
> > not necessarily andx commands.
> > I see a tcp frame with multiple smb commands going over to Windows XP
> > server and the server either responds to the first command and ignores rest
> > or does not respond and cifs client reconnects thinking server is not
> > responding.
> > I see the same problem with samba server (cifs client
> > reconnecting after logging
> > server does not respond or No response for/to cmd), just that I have not been
> > able to capture the wireshark trace successfully (unpredictable timing and
> > too much traffic, wireshark dropping packets etc.).
> >
> > cifs client does not do this (bundling multiple smb
> > commands) conciously, I think tcp does club them together
> > and if tcp is doing that, I do not know why and how to
> > prevent it and if it can't be prevented, would be nice if
> > samba server can tackle them.
> This sounds like a *very* weird bug in either the client
> framing or XP. If the client does correct smb framing, i.e.
> the 4-byte length header, Samba should really not have a
> problem with it. And I very much doubt that XP has a bug
> here.
> What client is that?
> Volker

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