mount.cifs - mount using the Common Internet File System (CIFS)


   mount.cifs {service} {mount-point} [-o options]


   This tool is part of the cifs-utils suite.

   mount.cifs mounts a Linux CIFS filesystem. It is usually invoked
   indirectly by the mount(8) command when using the "-t cifs" option.
   This command only works in Linux, and the kernel must support the cifs
   filesystem. The CIFS protocol is the successor to the SMB protocol and
   is supported by most Windows servers and many other commercial servers
   and Network Attached Storage appliances as well as by the popular Open
   Source server Samba.

   The mount.cifs utility attaches the UNC name (exported network
   resource) specified as service (using //server/share syntax, where
   "server" is the server name or IP address and "share" is the name of
   the share) to the local directory mount-point.

   Options to mount.cifs are specified as a comma-separated list of
   key=value pairs. It is possible to send options other than those listed
   here, assuming that the cifs filesystem kernel module (cifs.ko)
   supports them. Unrecognized cifs mount options passed to the cifs vfs
   kernel code will be logged to the kernel log.

   mount.cifs causes the cifs vfs to launch a thread named cifsd. After
   mounting it keeps running until the mounted resource is unmounted
   (usually via the umount utility).

   mount.cifs -V command displays the version of cifs mount helper.

   modinfo cifs command displays the version of cifs module.


       specifies the username to connect as. If this is not given, then
       the environment variable USER is used.

       Earlier versions of mount.cifs also allowed one to specify the
       username in a "user%password" or "workgroup/user" or
       "workgroup/user%password" to allow the password and workgroup to be
       specified as part of the username. Support for those alternate
       username formats is now deprecated and should no longer be used.
       Users should use the discrete "password=" and "domain=" to specify
       those values. While some versions of the cifs kernel module accept
       "user=" as an abbreviation for this option, its use can confuse the
       standard mount program into thinking that this is a non-superuser
       mount. It is therefore recommended to use the full "username="
       option name.

       specifies the CIFS password. If this option is not given then the
       environment variable PASSWD is used. If the password is not
       specified directly or indirectly via an argument to mount,
       mount.cifs will prompt for a password, unless the guest option is

       Note that a password which contains the delimiter character (i.e. a
       comma ,) will fail to be parsed correctly on the command line.
       However, the same password defined in the PASSWD environment
       variable or via a credentials file (see below) or entered at the
       password prompt will be read correctly.

       specifies a file that contains a username and/or password and
       optionally the name of the workgroup. The format of the file is:


       This is preferred over having passwords in plaintext in a shared
       file, such as /etc/fstab. Be sure to protect any credentials file

       sets the uid that will own all files or directories on the mounted
       filesystem when the server does not provide ownership information.
       It may be specified as either a username or a numeric uid. When not
       specified, the default is uid 0. The mount.cifs helper must be at
       version 1.10 or higher to support specifying the uid in non-numeric
       form. See the section on FILE AND DIRECTORY OWNERSHIP AND
       PERMISSIONS below for more information.

       instructs the client to ignore any uid provided by the server for
       files and directories and to always assign the owner to be the
       value of the uid= option. See the section on FILE AND DIRECTORY
       OWNERSHIP AND PERMISSIONS below for more information.

       sets the uid of the owner of the credentials cache. This is
       primarily useful with sec=krb5. The default is the real uid of the
       process performing the mount. Setting this parameter directs the
       upcall to look for a credentials cache owned by that user.

       sets the gid that will own all files or directories on the mounted
       filesystem when the server does not provide ownership information.
       It may be specified as either a groupname or a numeric gid. When
       not specified, the default is gid 0. The mount.cifs helper must be
       at version 1.10 or higher to support specifying the gid in
       non-numeric form. See the section on FILE AND DIRECTORY OWNERSHIP
       AND PERMISSIONS below for more information.

       instructs the client to ignore any gid provided by the server for
       files and directories and to always assign the owner to be the
       value of the gid= option. See the section on FILE AND DIRECTORY
       OWNERSHIP AND PERMISSIONS below for more information.

       sets the port number on which the client will attempt to contact
       the CIFS server. If this value is specified, look for an existing
       connection with this port, and use that if one exists. If one
       doesn't exist, try to create a new connection on that port. If that
       connection fails, return an error. If this value isn't specified,
       look for an existing connection on port 445 or 139. If no such
       connection exists, try to connect on port 445 first and then port
       139 if that fails. Return an error if both fail.

       Specify the server netbios name (RFC1001 name) to use when
       attempting to setup a session to the server. Although rarely needed
       for mounting to newer servers, this option is needed for mounting
       to some older servers (such as OS/2 or Windows 98 and Windows ME)
       since when connecting over port 139 they, unlike most newer
       servers, do not support a default server name. A server name can be
       up to 15 characters long and is usually uppercased.

       Synonym for servernetbiosname.

       When mounting to servers via port 139, specifies the RFC1001 source
       name to use to represent the client netbios machine name when doing
       the RFC1001 netbios session initialize.

       If the server does not support the CIFS Unix extensions this
       overrides the default file mode.

       If the server does not support the CIFS Unix extensions this
       overrides the default mode for directories.

       sets the destination IP address. This option is set automatically
       if the server name portion of the requested UNC name can be
       resolved so rarely needs to be specified by the user.

       sets the domain (workgroup) of the user

       dont prompt for a password

       Charset used to convert local path names to and from Unicode.
       Unicode is used by default for network path names if the server
       supports it. If iocharset is not specified then the nls_default
       specified during the local client kernel build will be used. If
       server does not support Unicode, this parameter is unused.

       mount read-only

       mount read-write

       If the CIFS Unix extensions are negotiated with the server the
       client will attempt to set the effective uid and gid of the local
       process on newly created files, directories, and devices (create,
       mkdir, mknod). If the CIFS Unix Extensions are not negotiated, for
       newly created files and directories instead of using the default
       uid and gid specified on the the mount, cache the new files uid
       and gid locally which means that the uid for the file can change
       when the inode is reloaded (or the user remounts the share).

       The client will not attempt to set the uid and gid on on newly
       created files, directories, and devices (create, mkdir, mknod)
       which will result in the server setting the uid and gid to the
       default (usually the server uid of the user who mounted the share).
       Letting the server (rather than the client) set the uid and gid is
       the default.If the CIFS Unix Extensions are not negotiated then the
       uid and gid for new files will appear to be the uid (gid) of the
       mounter or the uid (gid) parameter specified on the mount.

       Client does permission checks (vfs_permission check of uid and gid
       of the file against the mode and desired operation), Note that this
       is in addition to the normal ACL check on the target machine done
       by the server software. Client permission checking is enabled by

       Client does not do permission checks. This can expose files on this
       mount to access by other users on the local client system. It is
       typically only needed when the server supports the CIFS Unix
       Extensions but the UIDs/GIDs on the client and server system do not
       match closely enough to allow access by the user doing the mount.
       Note that this does not affect the normal ACL check on the target
       machine done by the server software (of the server ACL against the
       user name provided at mount time).

       Instructs the server to maintain ownership and permissions in
       memory that cant be stored on the server. This information can
       disappear at any time (whenever the inode is flushed from the
       cache), so while this may help make some applications work, its
       behavior is somewhat unreliable. See the section below on FILE AND
       DIRECTORY OWNERSHIP AND PERMISSIONS for more information.

       Cache mode. See the section below on CACHE COHERENCY for details.
       Allowed values are:

       *   none: do not cache file data at all

       *   strict: follow the CIFS/SMB2 protocol strictly

       *   loose: allow loose caching semantics

       The default in kernels prior to 3.7 was "loose". As of kernel 3.7
       the default is "strict".

       Do not do inode data caching on files opened on this mount. This
       precludes mmaping files on this mount. In some cases with fast
       networks and little or no caching benefits on the client (e.g. when
       the application is doing large sequential reads bigger than page
       size without rereading the same data) this can provide better
       performance than the default behavior which caches reads
       (readahead) and writes (writebehind) through the local Linux client
       pagecache if oplock (caching token) is granted and held. Note that
       direct allows write operations larger than page size to be sent to
       the server. On some kernels this requires the cifs.ko module to be
       built with the CIFS_EXPERIMENTAL configure option.

       This option is will be deprecated in 3.7. Users should use
       cache=none instead on more recent kernels.

       Use for switching on strict cache mode. In this mode the client
       reads from the cache all the time it has Oplock Level II, otherwise
       - read from the server. As for write - the client stores a data in
       the cache in Exclusive Oplock case, otherwise - write directly to
       the server.

       This option is will be deprecated in 3.7. Users should use
       cache=strict instead on more recent kernels.

       Forward pid of a process who opened a file to any read or write
       operation on that file. This prevent applications like WINE from
       failing on read and write if we use mandatory brlock style.

       Translate six of the seven reserved characters (not backslash, but
       including the colon, question mark, pipe, asterik, greater than and
       less than characters) to the remap range (above 0xF000), which also
       allows the CIFS client to recognize files created with such
       characters by Windowss POSIX emulation. This can also be useful
       when mounting to most versions of Samba (which also forbids
       creating and opening files whose names contain any of these seven
       characters). This has no effect if the server does not support
       Unicode on the wire. Please note that the files created with
       mapchars mount option may not be accessible if the share is mounted
       without that option.

       Do not translate any of these seven characters (default)

       currently unimplemented

       (default) currently unimplemented

       The program accessing a file on the cifs mounted file system will
       hang when the server crashes.

       (default) The program accessing a file on the cifs mounted file
       system will not hang when the server crashes and will return errors
       to the user application.

       Do not allow POSIX ACL operations even if server would support

       The CIFS client can get and set POSIX ACLs (getfacl, setfacl) to
       Samba servers version 3.0.10 and later. Setting POSIX ACLs requires
       enabling both CIFS_XATTR and then CIFS_POSIX support in the CIFS
       configuration options when building the cifs module. POSIX ACL
       support can be disabled on a per mount basis by specifying "noacl"
       on mount.

       This option is used to map CIFS/NTFS ACLs to/from Linux permission
       bits, map SIDs to/from UIDs and GIDs, and get and set Security

       DESCRIPTORS for more information.

       File access by this user shall be done with the backup intent flag
       set. Either a name or an id must be provided as an argument, there
       are no default values.

       See section ACCESSING FILES WITH BACKUP INTENT for more details

       File access by users who are members of this group shall be done
       with the backup intent flag set. Either a name or an id must be
       provided as an argument, there are no default values.

       See section ACCESSING FILES WITH BACKUP INTENT for more details

       Request case insensitive path name matching (case sensitive is the
       default if the server suports it).

       Synonym for nocase.

       Security mode. Allowed values are:

       *   none - attempt to connection as a null user (no name)

       *   krb5 - Use Kerberos version 5 authentication

       *   krb5i - Use Kerberos authentication and forcibly enable packet

       *   ntlm - Use NTLM password hashing

       *   ntlmi - Use NTLM password hashing and force packet signing

       *   ntlmv2 - Use NTLMv2 password hashing

       *   ntlmv2i - Use NTLMv2 password hashing and force packet signing

       *   ntlmssp - Use NTLMv2 password hashing encapsulated in Raw
           NTLMSSP message

       *   ntlmsspi - Use NTLMv2 password hashing encapsulated in Raw
           NTLMSSP message, and force packet signing

       The default in mainline kernel versions prior to v3.8 was sec=ntlm.
       In v3.8, the default was changed to sec=ntlmssp.

       If the server requires signing during protocol negotiation, then it
       may be enabled automatically. Packet signing may also be enabled
       automatically if it's enabled in /proc/fs/cifs/SecurityFlags.

       Do not send byte range lock requests to the server. This is
       necessary for certain applications that break with cifs style
       mandatory byte range locks (and most cifs servers do not yet
       support requesting advisory byte range locks).

       When the CIFS Unix Extensions are not negotiated, attempt to create
       device files and fifos in a format compatible with Services for
       Unix (SFU). In addition retrieve bits 10-12 of the mode via the
       SETFILEBITS extended attribute (as SFU does). In the future the
       bottom 9 bits of the mode mode also will be emulated using queries
       of the security descriptor (ACL). [NB: requires version 1.39 or
       later of the CIFS VFS. To recognize symlinks and be able to create
       symlinks in an SFU interoperable form requires version 1.40 or
       later of the CIFS VFS kernel module.

       Use inode numbers (unique persistent file identifiers) returned by
       the server instead of automatically generating temporary inode
       numbers on the client. Although server inode numbers make it easier
       to spot hardlinked files (as they will have the same inode numbers)
       and inode numbers may be persistent (which is userful for some
       sofware), the server does not guarantee that the inode numbers are
       unique if multiple server side mounts are exported under a single
       share (since inode numbers on the servers might not be unique if
       multiple filesystems are mounted under the same shared higher level
       directory). Note that not all servers support returning server
       inode numbers, although those that support the CIFS Unix
       Extensions, and Windows 2000 and later servers typically do support
       this (although not necessarily on every local server filesystem).
       Parameter has no effect if the server lacks support for returning
       inode numbers or equivalent. This behavior is enabled by default.

       Client generates inode numbers itself rather than using the actual
       ones from the server.

       See section INODE NUMBERS for more information.

       Disable the CIFS Unix Extensions for this mount. This can be useful
       in order to turn off multiple settings at once. This includes POSIX
       acls, POSIX locks, POSIX paths, symlink support and retrieving
       uids/gids/mode from the server. This can also be useful to work
       around a bug in a server that supports Unix Extensions.

       See section INODE NUMBERS for more information.

       Do not allow getfattr/setfattr to get/set xattrs, even if server
       would support it otherwise. The default is for xattr support to be

       Maximum amount of data that the kernel will request in a read
       request in bytes. Prior to kernel 3.2.0, the default was 16k, and
       the maximum size was limited by the CIFSMaxBufSize module
       parameter. As of kernel 3.2.0, the behavior varies according to
       whether POSIX extensions are enabled on the mount and the server
       supports large POSIX reads. If they are, then the default is 1M,
       and the maxmimum is 16M. If they are not supported by the server,
       then the default is 60k and the maximum is around 127k. The reason
       for the 60k is because it's the maximum size read that windows
       servers can fill. Note that this value is a maximum, and the client
       may settle on a smaller size to accomodate what the server
       supports. In kernels prior to 3.2.0, no negotiation is performed.

       Maximum amount of data that the kernel will send in a write request
       in bytes. Prior to kernel 3.0.0, the default and maximum was 57344
       (14 * 4096 pages). As of 3.0.0, the default depends on whether the
       client and server negotiate large writes via POSIX extensions. If
       they do, then the default is 1M, and the maximum allowed is 16M. If
       they do not, then the default is 65536 and the maximum allowed is

       Note that this value is just a starting point for negotiation in
       3.0.0 and up. The client and server may negotiate this size
       downward according to the server's capabilities. In kernels prior
       to 3.0.0, no negotiation is performed. It can end up with an
       existing superblock if this value isn't specified or it's greater
       or equal than the existing one.

       Enable local disk caching using FS-Cache for CIFS. This option
       could be useful to improve performance on a slow link, heavily
       loaded server and/or network where reading from the disk is faster
       than reading from the server (over the network). This could also
       impact the scalability positively as the number of calls to the
       server are reduced. But, be warned that local caching is not
       suitable for all workloads, for e.g., read-once type workloads. So,
       you need to consider carefully the situation/workload before using
       this option. Currently, local disk caching is enabled for CIFS
       files opened as read-only.

       NOTE: This feature is available only in the recent kernels that
       have been built with the kernel config option CONFIG_CIFS_FSCACHE.
       You also need to have cachefilesd daemon installed and running to
       make the cache operational.

       Map user accesses to individual credentials when accessing the
       server. By default, CIFS mounts only use a single set of user
       credentials (the mount credentials) when accessing a share. With
       this option, the client instead creates a new session with the
       server using the user's credentials whenever a new user accesses
       the mount. Further accesses by that user will also use those
       credentials. Because the kernel cannot prompt for passwords,
       multiuser mounts are limited to mounts using sec= options that
       don't require passwords.

       With this change, it's feasible for the server to handle
       permissions enforcement, so this option also implies "noperm".
       Furthermore, when unix extensions aren't in use and the
       administrator has not overriden ownership using the uid= or gid=
       options, ownership of files is presented as the current user
       accessing the share.

       The time (in seconds) that the CIFS client caches attributes of a
       file or directory before it requests attribute information from a
       server. During this period the changes that occur on the server
       remain undetected until the client checks the server again.

       By default, the attribute cache timeout is set to 1 second. This
       means more frequent on-the-wire calls to the server to check
       whether attributes have changed which could impact performance.
       With this option users can make a tradeoff between performance and
       cache metadata correctness, depending on workload needs. Shorter
       timeouts mean better cache coherency, but frequent increased number
       of calls to the server. Longer timeouts mean a reduced number of
       calls to the server but looser cache coherency. The actimeo value
       is a positive integer that can hold values between 0 and a maximum
       value of 2^30 * HZ (frequency of timer interrupt) setting.

       If unix extensions are enabled on a share, then the client will
       typically allow filenames to include any character besides '/' in a
       pathname component, and will use forward slashes as a pathname
       delimiter. This option prevents the client from attempting to
       negotiate the use of posix-style pathnames to the server.

       Inverse of noposixpaths.

       It's possible to mount a subdirectory of a share. The preferred way
       to do this is to append the path to the UNC when mounting. However,
       it's also possible to do the same by setting this option and
       providing the path there.

       SMB protocol version. Allowed values are:

       *   1.0 - The classic CIFS/SMBv1 protocol. This is the default.

       *   2.0 - The SMBv2.002 protocol. This was initially introduced in
           Windows Vista Service Pack 1, and Windows Server 2008. Note
           that the initial release version of Windows Vista spoke a
           slightly different dialect (2.000) that is not supported.

       *   2.1 - The SMBv2.1 protocol that was introduced in Microsoft
           Windows 7 and Windows Server 2008R2.

       *   3.0 - The SMBv3.0 protocol that was introduced in Microsoft
           Windows 8 and Windows Server 2012.

       Note too that while this option governs the protocol version used,
       not all features of each version are available.

       Print additional debugging information for the mount. Note that
       this parameter must be specified before the -o. For example:

       mount -t cifs //server/share /mnt --verbose -o user=username


   Its generally preferred to use forward slashes (/) as a delimiter in
   service names. They are considered to be the "universal delimiter"
   since they are generally not allowed to be embedded within path
   components on Windows machines and the client can convert them to
   blackslashes (\) unconditionally. Conversely, backslash characters are
   allowed by POSIX to be part of a path component, and cant be
   automatically converted in the same way.

   mount.cifs will attempt to convert backslashes to forward slashes where
   its able to do so, but it cannot do so in any path component following
   the sharename.


   When Unix Extensions are enabled, we use the actual inode number
   provided by the server in response to the POSIX calls as an inode

   When Unix Extensions are disabled and "serverino" mount option is
   enabled there is no way to get the server inode number. The client
   typically maps the server-assigned "UniqueID" onto an inode number.

   Note that the UniqueID is a different value from the server inode
   number. The UniqueID value is unique over the scope of the entire
   server and is often greater than 2 power 32. This value often makes
   programs that are not compiled with LFS (Large File Support), to
   trigger a glibc EOVERFLOW error as this wont fit in the target
   structure field. It is strongly recommended to compile your programs
   with LFS support (i.e. with -D_FILE_OFFSET_BITS=64) to prevent this
   problem. You can also use "noserverino" mount option to generate inode
   numbers smaller than 2 power 32 on the client. But you may not be able
   to detect hardlinks properly.


   With a network filesystem such as CIFS or NFS, the client must contend
   with the fact that activity on other clients or the server could change
   the contents or attributes of a file without the client being aware of
   it. One way to deal with such a problem is to mandate that all file
   accesses go to the server directly. This is performance prohibitive
   however, so most protocols have some mechanism to allow the client to
   cache data locally.

   The CIFS protocol mandates (in effect) that the client should not cache
   file data unless it holds an opportunistic lock (aka oplock) or a
   lease. Both of these entities allow the client to guarantee certain
   types of exclusive access to a file so that it can access its contents
   without needing to continually interact with the server. The server
   will call back the client when it needs to revoke either of them and
   allow the client a certain amount of time to flush any cached data.

   The cifs client uses the kernel's pagecache to cache file data. Any I/O
   that's done through the pagecache is generally page-aligned. This can
   be problematic when combined with byte-range locks as Windows' locking
   is mandatory and can block reads and writes from occurring.

   cache=none means that the client never utilizes the cache for normal
   reads and writes. It always accesses the server directly to satisfy a
   read or write request.

   cache=strict means that the client will attempt to follow the CIFS/SMB2
   protocol strictly. That is, the cache is only trusted when the client
   holds an oplock. When the client does not hold an oplock, then the
   client bypasses the cache and accesses the server directly to satisfy a
   read or write request. By doing this, the client avoids problems with
   byte range locks. Additionally, byte range locks are cached on the
   client when it holds an oplock and are "pushed" to the server when that
   oplock is recalled.

   cache=loose allows the client to use looser protocol semantics which
   can sometimes provide better performance at the expense of cache
   coherency. File access always involves the pagecache. When an oplock or
   lease is not held, then the client will attempt to flush the cache soon
   after a write to a file. Note that that flush does not necessarily
   occur before a write system call returns.

   In the case of a read without holding an oplock, the client will
   attempt to periodically check the attributes of the file in order to
   ascertain whether it has changed and the cache might no longer be
   valid. This mechanism is much like the one that NFSv2/3 use for cache
   coherency, but it particularly problematic with CIFS. Windows is quite
   "lazy" with respect to updating the "LastWriteTime" field that the
   client uses to verify this. The effect is that cache=loose can cause
   data corruption when multiple readers and writers are working on the
   same files.

   Because of this, when multiple clients are accessing the same set of
   files, then cache=strict is recommended. That helps eliminate problems
   with cache coherency by following the CIFS/SMB2 protocols more

   Note too that no matter what caching model is used, the client will
   always use the pagecache to handle mmap'ed files. Writes to mmap'ed
   files are only guaranteed to be flushed to the server when msync() is
   called, or on close().

   The default in kernels prior to 3.7 was "loose". As of 3.7, the default
   is "strict".


   This option is used to work with file objects which posses Security
   Descriptors and CIFS/NTFS ACL instead of UID, GID, file permission
   bits, and POSIX ACL as user authentication model. This is the most
   common authentication model for CIFS servers and is the one used by

   Support for this requires both CIFS_XATTR and CIFS_ACL support in the
   CIFS configuration options when building the cifs module.

   A CIFS/NTFS ACL is mapped to file permission bits using an algorithm
   specified in the following Microsoft TechNet document:


   In order to map SIDs to/from UIDs and GIDs, the following is required:

   *   a kernel upcall to the cifs.idmap utility set up via request-

   *   winbind support configured via nsswitch.conf(5) and smb.conf(5)

   Please refer to the respective manpages of cifs.idmap(8) and
   winbindd(8) for more information.

   Security descriptors for a file object can be retrieved and set
   directly using extended attribute named system.cifs_acl. The security
   descriptors presented via this interface are "raw" blobs of data and
   need a userspace utility to either parse and format or to assemble it
   such as getcifsacl(1) and setcifsacl(1) respectively.

   Some of the things to consider while using this mount option:

   *   There may be an increased latency when handling metadata due to
       additional requests to get and set security descriptors.

   *   The mapping between a CIFS/NTFS ACL and POSIX file permission bits
       is imperfect and some ACL information may be lost in the

   *   If either upcall to cifs.idmap is not setup correctly or winbind is
       not configured and running, ID mapping will fail. In that case uid
       and gid will default to either to those values of the share or to
       the values of uid and/or gid mount options if specified.


   For an user on the server, desired access to a file is determined by
   the permissions and rights associated with that file.  This is
   typically accomplished using owenrship and ACL.  For a user who does
   not have access rights to a file, it is still possible to access that
   file for a specific or a targeted purpose by granting special rights.
   One of the specific purposes is to access a file with the intent to
   either backup or restore i.e. backup intent.  The right to access a
   file with the backup intent can typically be granted by making that
   user a part of the built-in group Backup Operators.  Thus, when this
   user attempts to open a file with the backup intent, open request is
   sent by setting the bit FILE_OPEN_FOR_BACKUP_INTENT as one of the

   As an example, on a Windows server, a user named testuser, cannot open
   this file with such a security descriptor.

   GROUP:Domain Users

   But the user testuser, if it becomes part of the group Backup
   Operators, can open the file with the backup intent.

   Any user on the client side who can authenticate as such a user on the
   server, can access the files with the backup intent. But it is
   desirable and preferable for security reasons amongst many, to restrict
   this special right.

   The mount option backupuid is used to restrict this special right to a
   user which is specified by either a name or an id. The mount option
   backupgid is used to restrict this special right to the users in a
   group which is specified by either a name or an id. Only users maching
   either backupuid or backupgid shall attempt to access files with backup
   intent. These two mount options can be used together.


   The core CIFS protocol does not provide unix ownership information or
   mode for files and directories. Because of this, files and directories
   will generally appear to be owned by whatever values the uid= or gid=
   options are set, and will have permissions set to the default file_mode
   and dir_mode for the mount. Attempting to change these values via
   chmod/chown will return success but have no effect.

   When the client and server negotiate unix extensions, files and
   directories will be assigned the uid, gid, and mode provided by the
   server. Because CIFS mounts are generally single-user, and the same
   credentials are used no matter what user accesses the mount, newly
   created files and directories will generally be given ownership
   corresponding to whatever credentials were used to mount the share.

   If the uids and gids being used do not match on the client and
   server, the forceuid and forcegid options may be helpful. Note however,
   that there is no corresponding option to override the mode. Permissions
   assigned to a file when forceuid or forcegid are in effect may not
   reflect the the real permissions.

   When unix extensions are not negotiated, its also possible to emulate
   them locally on the server using the "dynperm" mount option. When this
   mount option is in effect, newly created files and directories will
   receive what appear to be proper permissions. These permissions are not
   stored on the server however and can disappear at any time in the
   future (subject to the whims of the kernel flushing out the inode
   cache). In general, this mount option is discouraged.

   Its also possible to override permission checking on the client
   altogether via the noperm option. Server-side permission checks cannot
   be overriden. The permission checks done by the server will always
   correspond to the credentials used to mount the share, and not
   necessarily to the user who is accessing the share.


   The variable USER may contain the username of the person to be used to
   authenticate to the server. The variable can be used to set both
   username and password by using the format username%password.

   The variable PASSWD may contain the password of the person using the

   The variable PASSWD_FILE may contain the pathname of a file to read the
   password from. A single line of input is read and used as the password.


   This command may be used only by root, unless installed setuid, in
   which case the noeexec and nosuid mount flags are enabled. When
   installed as a setuid program, the program follows the conventions set
   forth by the mount program for user mounts, with the added restriction
   that users must be able to chdir() into the mountpoint prior to the
   mount in order to be able to mount onto it.

   Some samba client tools like smbclient(8) honour client-side
   configuration parameters present in smb.conf. Unlike those client
   tools, mount.cifs ignores smb.conf completely.


   The primary mechanism for making configuration changes and for reading
   debug information for the cifs vfs is via the Linux /proc filesystem.
   In the directory /proc/fs/cifs are various configuration files and
   pseudo files which can display debug information. There are additional
   startup options such as maximum buffer size and number of buffers which
   only may be set when the kernel cifs vfs (cifs.ko module) is loaded.
   These can be seen by running the modinfo utility against the file
   cifs.ko which will list the options that may be passed to cifs during
   module installation (device driver load). For more information see the
   kernel file fs/cifs/README.


   Mounting using the CIFS URL specification is currently not supported.

   The credentials file does not handle usernames or passwords with
   leading space.

   Note that the typical response to a bug report is a suggestion to try
   the latest version first. So please try doing that first, and always
   include which versions you use of relevant software when reporting bugs
   (minimum: mount.cifs (try mount.cifs -V), kernel (see /proc/version)
   and server type you are trying to contact.


   This man page is correct for version 1.74 of the cifs vfs filesystem
   (roughly Linux kernel 3.0).


   cifs.upcall(8), getcifsacl(1), setcifsacl(1)

   Documentation/filesystems/cifs.txt and fs/cifs/README in the linux
   kernel source tree may contain additional options and information.


   Steve French

   The syntax and manpage were loosely based on that of smbmount. It was
   converted to Docbook/XML by Jelmer Vernooij.

   The maintainer of the Linux cifs vfs and the userspace tool mount.cifs
   is Steve French. The Linux CIFS Mailing list is the preferred place to
   ask questions regarding these programs.


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