Anyone know what bit 4 is in the flags2 field on the SMB header?

Christopher R. Hertel crh at
Thu Feb 8 22:12:58 GMT 2007

My book has bits 3,4,5 and 7,8,9,10 as being "reserved".  That's probably
based on the SNIA docs as well as source code from Samba and jCIFS.

It's possible, I suppose, that Windows systems just ignore these bits and
that there is no behavior associated with their being set.  I'm interested
in finding out otherwise as a couple of people working on implementations
have sent me queries over the last few months.

Chris -)-----

Gerald (Jerry) Carter wrote:
> Chris,
>> I have had this question several times recently.  The best 
>> I could find was a cryptic comment in smb.h:
>> #define FLAGS2_WIN2K_SIGNATURE     0xC852 /* Hack alert ! For now... JRA. */
> Thanks.  Except Win2K and XP both set bit 4 but Vista
> does not (neither does NT4).  I've got %a expansion
> working with Vista based on that flag being cleared.  And
> to avoid any confusion, I know bit 3 in the SNIA draft
> says its reserved (counting from 0) so I'm looking for one
> bit up from that.
> cheers, jerry

"Implementing CIFS - the Common Internet FileSystem" ISBN: 013047116X
Samba Team --     -)-----   Christopher R. Hertel
jCIFS Team --   -)-----   ubiqx development, uninq.
ubiqx Team --     -)-----   crh at
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