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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 <configuration 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, Windows 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) . This man page will not describe the
services, but will concentrate on the administrative aspects of running the
server.
Please note that there are significant security implications 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 during 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
connections 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 serious warnings will be logged. Level 1 is a reasonable level for
day to day running - it generates a small amount of information about
operations carried out.
Levels above 1 will generate considerable amounts of log data, and
should only be used when investigating 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 override the log
levelfile.
-l <log directory>
If specified, log directory specifies a log directory 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 controlled by the max
log size option in the smb.conf(5)file. Beware: If the directory
specified does not exist, smbd will log to the default debug log
location defined at compile time.
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 services 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 descriptions
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-daemon, this file must
contain suitable startup information 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 systems 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 systems. 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 services, 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 specific 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
configuration files may need a line added for session support.
VERSION
This man page is correct for version 2.2 of the Samba suite.
TROUBLESHOOTING
One of the common causes of difficulty when installing Samba and SWAT is
the existsnece of some type of firewall or port filtering software on the
Samba server. Make sure that the appropriate ports outlined in this man
page are available on the server and are not currently being blocked by
some type of security software such as iptables or "port sentry". For more
troubleshooting information, refer to the additional documentation included
in the Samba distribution.
Most diagnostics issued by the server are logged in a specified log file.
The log file name is specified at compile 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. Unfortunately, at the time
this man page was created, there are too many diagnostics available in the
source code to warrant 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 performance.
SEE ALSO
hosts_access(5), inetd(8), nmbd(8), smb.conf(5) , smbclient(1) , and the
Internet RFC's rfc1001.txt, rfc1002.txt. In addition the CIFS (formerly
SMB) specification 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, available 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
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Index for
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