Flags field

This field contains 8 individual flags, numbered from least significant to most significant, and have the following meanings:

Bit

===
Meaning

================================================
Earliest Dialect
============
0 When set (returned) from the server in the SMB_COM_NEGOTIATE response SMB, this bit indicates that the server supports the "sub dialect" consisting of the LockandRead and WriteandUnlock protocols defined later in this document. LANMAN1.0
1 When on (on an SMB request being sent to the server), the client guarantees that there is a receive buffer posted such that a send without acknowledgment can be used by the server to respond to the client's request.
2 Reserved (must be zero).
3 When on, all pathnames in this SMB must be treated as caseless. When off, the pathnames are case sensitive. LANMAN1.0
4 When on (in SMB_COM_SESSION_SETUP_ANDX defined later in this document), all paths sent to the server by the client are already canonicalized. This means that file/directory names are in upper case, are valid characters, . and .. have been removed, and single backslashes are used as separators. LANMAN1.0
5 When on (in SMB_COM_OPEN, SMB_COM_CREATE and SMB_COM_CREATE_NEW), this indicates that the client is requesting that the file be "opportunistically" locked if this process is the only process which has the file open at the time of the open request. If the server "grants" this oplock request, then this bit should remain set in the corresponding response SMB to indicate to the client that the oplock request was granted. See the discussion of "oplock" in the sections defining the SMB_COM_OPEN_ANDX and SMB_COM_LOCKING_ANDX protocols later in this document (this bit has the same function as bit 1 of Flags if the SMB_COM_OPEN_ANDX SMB). LANMAN1.0
6 When on (in core protocols SMB_COM_OPEN_ANDX, SMB_COM_CREATE and SMB_COM_CREATE_NEW), this indicates that the server should notify the client on any action which can modify the file (delete, setattrib, rename, etc.) by another client. If not set, the server need only notify the client about another open request by a different client. See the discussion of "oplock" in the sections defining the SMB_COM_OPEN_ANDX and SMB_COM_LOCKING_ANDX SMBs later in this document (this bit has the same function as bit 2 of smb_flags of the SMB_COM_OPEN_ANDX SMB). Bit6 only has meaning if bit5 is set.. LANMAN1.0
7 When on, this SMB is being sent from the server in response to a client request. The Command field usually contains the same value in a protocol request from the client to the server as in the matching response from the server to the client. This bit unambiguously distinguishes the command request from the command response. PC NETWORK PROGRAM 1.0