cifs – Microsoft(tm) Windows network filesystem client

cifs [ –bDiv ] [ –d debug ] [ –a auth–method ] [ –s srvname ] [ –n called–name ] [ –k keyparam ] [ –m mntpnt ] [ –t dfs–timeout ] host [ share ... ]

Cifs translates between Microsoft's file–sharing protocol (a.k.a. CIFS or SMB) and 9P, allowing Plan 9 clients to mount file systems (shares or trees in MS terminology) published by such servers.

The root of the mounted directory contains one subdirectory per share, and a few virtual files give additional information. The arguments are:
a auth–methodCifs authenticates using ntlmv2 by default, but alternative strategies may be selected using this option. Cifs eschews cleartext authentication, however it may be enabled with the plain auth method. The list of currently–supported methods is printed if no method name is supplied.
Windows server 2003 requires the ntlmv2 method by default, though it can be configured to be more flexible.
b           Enable file ownership resolution in stat(2) calls. This requires an open and close per file and thus will slow cifs considerably; its use is not recommended.
d debug      followed by non–whitespace separated list of debug options debug writes specific debug output to file descriptor 2. See source for more information.
D           9P request debug.
i           By default cifs attempts to enforce case significance file and directory names, though objects which differ only in their case still cannot co–exist in the same directory. The –i option disables this behaveiour.
k keyparam    lists extra parameters which will be passed to factotum(4) to select a specific key. The remote servers's domain is always included in the keyspec, under the assumption that all servers in a Windows domain share an authentication domain; thus cifs expects keys in factotum of the form:
key proto=pass dom=THEIR–DOMAIN service=cifs
user=MY–USERNAME !password=XYZZY
m mntpnt     set the mount point for the remote filesystem; the default is /n/host.
n called–nameThe CIFS protocol requires clients to know the NetBios name of the server they are attaching to, the Icalled–name. If this is not specified on the command line, cifs attempts to discover this name from the remote server. If this fails it will then try host, and finally it will try the name *SMBSERVER. –s srvname     post the service as /srv/srvname.
t dfs–timeout   sets the timeout in for DFS redirections – it defaults to 100ms. This is a reasonable minimum, it should have a value just greater than the RTT to the most distant server being accessed.
host          The address of the remote server to connect to.
share         A list of share names to attach on the remote server; if none is given, cifs will attempt to attach all shares published by the remote host.

Synthetic Files
Several synthetic files appear in the root of the mounted filesystem:
Shares         Contains a list of the currently attached shares, with fields giving the share name, the share type, disk free space / capacity, and a descriptive comment from the server.
Connection     Contains the username used for authentication, server's called name, server's domain, server's OS, the time slip between the local host and the server, the Maximum Transfer Unit (MTU) the server requested, and optionally a flag indicating only guest access has been granted. The second line
contains a list of capabilities offered by the server which is mainly of use for debugging cifs.
Users          Each line contains a user's name, the user's full name, and a descriptive comment.
Groups         Each line gives a group's name, and a list of the names of the users who are members of that group.
Sessions       Lists the users authenticated, the client machine's NetBios name or IP address, the time since the connection was established, and the time for which the connection has been idle.
Domains        One line per domain giving the domain name and a descriptive comment.
Workstations   One line per domain giving the domain name and a descriptive comment, the version number of the OS it is running, and comma–separated list of flags giving the features of that OS.
Dfsroot        Lists the top level DFS domains and the servers that provision them.
Dfscache       Contents of the DFS referal cache, giving the path prefix, the expiry time (or –1 for never), the measured RTT to the server in milliseconds, the server proximity (0 is local), the server name, and the share name on that server.

Cifs has been tested against aquarela, cifsd(8), Windows 95, NT4.0sp6, Windows server 2003, Windows server 2003, WinXP pro, Samba 2.0 (Pluto VideoSpace), and Samba 3.0.

Windows Vista require a hotfix (registry change) to support NTLMv2 without GSSAPI, see Alternatively the –a option can be used to force cifs to use one of the less secure authentication mechanisms.

Windows 7 has dropped support for RAP, which is used to generate the synthetic files offered by cifs. RAP is also used to enumerate the shares offered by the remote host so remote share names must always be specified on the command line.

The NetApp Filer was supported by earlier releases, however recent attempts to mount one have failed. Should a server be available it is likely that this could be easily fixed.


factotum(4), cifsd(8)

DFS support is unfinished, it will not follow referals that span servers.

Kerberos authentication is not supported.

NetBios name resolution is not supported, though it is now rarely used.

Cifs first appeared in Plan 9 from Bell Labs. It was updated to the author's latest revision for 9front (January, 2012).