SMBD(8) SMBD(8)
NAME
smbd - server to provide SMB/CIFS services to clients
SYNOPSIS
smbd [ -D ] [ -a ] [ -i ] [ -o ] [ -P ] [ -h ] [ -V
] [ -d <debug level> ] [ -l <log directory> ] [ -p
<port number> ] [ -O <socket option> ] [ -s <configura-
tion file> ]
DESCRIPTION
This program is part of the Samba suite.
smbd is the server daemon that provides filesharing and
printing services to Windows clients. The server provides
filespace and printer services to clients using the SMB
(or CIFS) protocol. This is compatible with the LanManager
protocol, and can service LanManager clients. These
include MSCLIENT 3.0 for DOS, Windows for Workgroups, Win-
dows 95/98/ME, Windows NT, Windows 2000, OS/2, DAVE for
Macintosh, and smbfs for Linux.
An extensive description of the services that the server
can provide is given in the man page for the configuration
file controlling the attributes of those services (see
smb.conf(5) services, but will concentrate on the adminis-
trative aspects of running the server.
Please note that there are significant security implica-
tions to running this server, and the smb.conf(5) manpage
should be regarded as mandatory reading before proceeding
with installation.
A session is created whenever a client requests one. Each
client gets a copy of the server for each session. This
copy then services all connections made by the client dur-
ing that session. When all connections from its client are
closed, the copy of the server for that client terminates.
The configuration file, and any files that it includes,
are automatically reloaded every minute, if they change.
You can force a reload by sending a SIGHUP to the server.
Reloading the configuration file will not affect connec-
tions to any service that is already established. Either
the user will have to disconnect from the service, or smbd
killed and restarted.
OPTIONS
-D If specified, this parameter causes the server to
operate as a daemon. That is, it detaches itself
and runs in the background, fielding requests on
the appropriate port. Operating the server as a
daemon is the recommended way of running smbd for
servers that provide more than casual use file and
print services. This switch is assumed if smbd is
executed on the command line of a shell.
-a If this parameter is specified, each new connection
will append log messages to the log file. This is
the default.
-i If this parameter is specified it causes the server
to run "interactively", not as a daemon, even if
the server is executed on the command line of a
shell. Setting this parameter negates the implicit
deamon mode when run from the command line.
-o If this parameter is specified, the log files will
be overwritten when opened. By default, smbd will
append entries to the log files.
-P Passive option. Causes smbd not to send any network
traffic out. Used for debugging by the developers
only.
-h Prints the help information (usage) for smbd.
-v Prints the version number for smbd.
-d <debug level>
debuglevel is an integer from 0 to 10. The default
value if this parameter is not specified is zero.
The higher this value, the more detail will be
logged to the log files about the activities of the
server. At level 0, only critical errors and seri-
ous warnings will be logged. Level 1 is a reason-
able level for day to day running - it generates a
small amount of information about operations car-
ried out.
Levels above 1 will generate considerable amounts
of log data, and should only be used when investi-
gating a problem. Levels above 3 are designed for
use only by developers and generate HUGE amounts of
log data, most of which is extremely cryptic.
Note that specifying this parameter here will over-
ride the log levelfile.
-l <log directory>
If specified, log directory specifies a log direc-
tory into which the "log.smbd" log file will be
created for informational and debug messages from
the running server. The log file generated is never
removed by the server although its size may be con-
trolled by the max log size option in the
smb.conf(5)file.
The default log directory is specified at compile
time.
-O <socket options>
See the socket options parameter in the smb.conf(5)
file for details.
-p <port number>
port number is a positive integer value. The
default value if this parameter is not specified is
139.
This number is the port number that will be used
when making connections to the server from client
software. The standard (well-known) port number for
the SMB over TCP is 139, hence the default. If you
wish to run the server as an ordinary user rather
than as root, most systems will require you to use
a port number greater than 1024 - ask your system
administrator for help if you are in this
situation.
In order for the server to be useful by most
clients, should you configure it on a port other
than 139, you will require port redirection ser-
vices on port 139, details of which are outlined in
rfc1002.txt section 4.3.5.
This parameter is not normally specified except in
the above situation.
-s <configuration file>
The file specified contains the configuration
details required by the server. The information in
this file includes server-specific information such
as what printcap file to use, as well as descrip-
tions of all the services that the server is to
provide. See smb.conf(5)for more information. The
default configuration file name is determined at
compile time.
FILES
/etc/inetd.conf
If the server is to be run by the inetd meta-dae-
mon, this file must contain suitable startup infor-
mation for the meta-daemon. See the
UNIX_INSTALL.html document for details.
/etc/rc
or whatever initialization script your system
uses).
If running the server as a daemon at startup, this
file will need to contain an appropriate startup
sequence for the server. See the UNIX_INSTALL.html
document for details.
/etc/services
If running the server via the meta-daemon inetd,
this file must contain a mapping of service name
(e.g., netbios-ssn) to service port (e.g., 139) and
protocol type (e.g., tcp). See the
UNIX_INSTALL.html document for details.
/usr/local/samba/lib/smb.conf
This is the default location of the smb.conf server
configuration file. Other common places that sys-
tems install this file are /usr/samba/lib/smb.conf
and /etc/smb.conf.
This file describes all the services the server is
to make available to clients. See smb.conf(5)for
more information.
LIMITATIONS
On some systems smbd cannot change uid back to root after
a setuid() call. Such systems are called trapdoor uid sys-
tems. If you have such a system, you will be unable to
connect from a client (such as a PC) as two different
users at once. Attempts to connect the second user will
result in access denied or similar.
ENVIRONMENT VARIABLES
PRINTER
If no printer name is specified to printable ser-
vices, most systems will use the value of this
variable (or lp if this variable is not defined) as
the name of the printer to use. This is not spe-
cific to the server, however.
PAM INTERACTION
Samba uses PAM for authentication (when presented with a
plaintext password), for account checking (is this account
disabled?) and for session management. The degree too
which samba supports PAM is restricted by the limitations
of the SMB protocol and the obey pam restricions smb.conf
paramater. When this is set, the following restrictions
apply:
o Account Validation: All acccesses to a samba server are
checked against PAM to see if the account is vaild, not
disabled and is permitted to login at this time. This
also applies to encrypted logins.
o Session Management: When not using share level secuirty,
users must pass PAM's session checks before access is
granted. Note however, that this is bypassed in share
level secuirty. Note also that some older pam configu-
ration files may need a line added for session support.
VERSION
This man page is correct for version 2.2 of the Samba
suite.
DIAGNOSTICS
Most diagnostics issued by the server are logged in a
specified log file. The log file name is specified at com-
pile time, but may be overridden on the command line.
The number and nature of diagnostics available depends on
the debug level used by the server. If you have problems,
set the debug level to 3 and peruse the log files.
Most messages are reasonably self-explanatory. Unfortu-
nately, at the time this man page was created, there are
too many diagnostics available in the source code to war-
rant describing each and every diagnostic. At this stage
your best bet is still to grep the source code and inspect
the conditions that gave rise to the diagnostics you are
seeing.
SIGNALS
Sending the smbd a SIGHUP will cause it to reload its
smb.conf configuration file within a short period of time.
To shut down a user's smbd process it is recommended that
SIGKILL (-9) NOT be used, except as a last resort, as this
may leave the shared memory area in an inconsistent state.
The safe way to terminate an smbd is to send it a SIGTERM
(-15) signal and wait for it to die on its own.
The debug log level of smbd may be raised or lowered using
smbcontrol(1) program (SIGUSR[1|2] signals are no longer
used in Samba 2.2). This is to allow transient problems to
be diagnosed, whilst still running at a normally low log
level.
Note that as the signal handlers send a debug write, they
are not re-entrant in smbd. This you should wait until
smbd is in a state of waiting for an incoming SMB before
issuing them. It is possible to make the signal handlers
safe by un-blocking the signals before the select call and
re-blocking them after, however this would affect perfor-
mance.
SEE ALSO
hosts_access(5), inetd(8), nmbd(8), smb.conf(5) , smb-
client(1) , and the Internet RFC's rfc1001.txt,
rfc1002.txt. In addition the CIFS (formerly SMB) specifi-
cation is available as a link from the Web page
http://samba.org/cifs/ <URL:http://samba.org/cifs/>.
AUTHOR
The original Samba software and related utilities were
created by Andrew Tridgell. Samba is now developed by the
Samba Team as an Open Source project similar to the way
the Linux kernel is developed.
The original Samba man pages were written by Karl Auer.
The man page sources were converted to YODL format
(another excellent piece of Open Source software, avail-
able at ftp://ftp.icce.rug.nl/pub/unix/
<URL:ftp://ftp.icce.rug.nl/pub/unix/>) and updated for the
Samba 2.0 release by Jeremy Allison. The conversion to
DocBook for Samba 2.2 was done by Gerald Carter
24 January 2002 SMBD(8)