path: root/docs/manpages/smbd.8

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.\" from a DocBook document.  docbook2man-spec can be found at:
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.\" Please send any bug reports, improvements, comments, patches, 
.\" etc. to Steve Cheng <steve@ggi-project.org>.
.TH "SMBD" "8" "10 October 2001" "" ""
.SH NAME
smbd \- server to provide SMB/CIFS services to clients
.SH SYNOPSIS
.sp
\fBsmbd\fR [ \fB-D\fR ]  [ \fB-a\fR ]  [ \fB-o\fR ]  [ \fB-P\fR ]  [ \fB-h\fR ]  [ \fB-V\fR ]  [ \fB-d <debug level>\fR ]  [ \fB-l <log file>\fR ]  [ \fB-p <port number>\fR ]  [ \fB-O <socket option>\fR ]  [ \fB-s <configuration file>\fR ] 
.SH "DESCRIPTION"
.PP
This program is part of the Samba suite.
.PP
\fBsmbd\fR 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.
.PP
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 \fIsmb.conf(5)
\fR. This man page will not describe the 
services, but will concentrate on the administrative aspects 
of running the server.
.PP
Please note that there are significant security 
implications to running this server, and the \fIsmb.conf(5)\fR
manpage should be regarded as mandatory reading before 
proceeding with installation.
.PP
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.
.PP
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 \fBsmbd\fR killed and restarted.
.SH "OPTIONS"
.TP
\fB-D\fR
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 \fBsmbd\fR for 
servers that provide more than casual use file and 
print services. This switch is assumed if \fBsmbd
\fRis executed on the command line of a shell.
.TP
\fB-a\fR
If this parameter is specified, each new 
connection will append log messages to the log file. 
This is the default.
.TP
\fB-o\fR
If this parameter is specified, the 
log files will be overwritten when opened. By default, 
\fBsmbd\fR will append entries to the log 
files.
.TP
\fB-P\fR
Passive option. Causes \fBsmbd\fR not to 
send any network traffic out. Used for debugging by 
the developers only.
.TP
\fB-h\fR
Prints the help information (usage) 
for \fBsmbd\fR.
.TP
\fB-v\fR
Prints the version number for 
\fBsmbd\fR.
.TP
\fB-d <debug level>\fR
\fIdebuglevel\fR 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.
.TP
\fB-l <log file>\fR
If specified, \fIlog file\fR 
specifies a log filename into which informational and debug 
messages from the running server will be logged. The log 
file generated is never removed by the server although 
its size may be controlled by the max log size
option in the \fI smb.conf(5)\fRfile. The default log 
file name is specified at compile time.
.TP
\fB-O <socket options>\fR
See the socket options
parameter in the \fIsmb.conf(5)
\fRfile for details.
.TP
\fB-p <port number>\fR
\fIport number\fR 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.
.TP
\fB-s <configuration file>\fR
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 \fI smb.conf(5)\fRfor more information.
The default configuration file name is determined at 
compile time.
.SH "FILES"
.TP
\fB\fI/etc/inetd.conf\fB\fR
If the server is to be run by the 
\fBinetd\fR meta-daemon, this file 
must contain suitable startup information for the 
meta-daemon. See the section INSTALLATION below.
.TP
\fB\fI/etc/rc\fB\fR
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 section INSTALLATION 
below.
.TP
\fB\fI/etc/services\fB\fR
If running the server via the 
meta-daemon \fBinetd\fR, 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 section INSTALLATION below.
.TP
\fB\fI/usr/local/samba/lib/smb.conf\fB\fR
This is the default location of the 
\fIsmb.conf\fR
server configuration file. Other common places that systems 
install this file are \fI/usr/samba/lib/smb.conf\fR 
and \fI/etc/smb.conf\fR.

This file describes all the services the server 
is to make available to clients. See  \fIsmb.conf(5)\fRfor more information.
.SH "LIMITATIONS"
.PP
On some systems \fBsmbd\fR 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.
.SH "ENVIRONMENTVARIABLES"
.TP
\fBPRINTER\fR
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.
.SH "INSTALLATION"
.PP
The location of the server and its support files 
is a matter for individual system administrators. The following 
are thus suggestions only.
.PP
It is recommended that the server software be installed 
under the \fI/usr/local/samba/\fR hierarchy, 
in a directory readable by all, writeable only by root. The server 
program itself should be executable by all, as users may wish to 
run the server themselves (in which case it will of course run 
with their privileges). The server should NOT be setuid. On some 
systems it may be worthwhile to make \fBsmbd\fR setgid to an empty group. 
This is because some systems may have a security hole where daemon 
processes that become a user can be attached to with a debugger. 
Making the \fBsmbd\fR file setgid to an empty group may prevent
this hole from being exploited. This security hole and the suggested
fix has only been confirmed on old versions (pre-kernel 2.0) of Linux
at the time this was written. It is possible that this hole only
exists in Linux, as testing on other systems has thus far shown them
to be immune.
.PP
The server log files should be put in a directory readable and
writeable only by root, as the log files may contain sensitive
information.
.PP
The configuration file should be placed in a directory 
readable and writeable only by root, as the configuration file 
controls security for the services offered by the server. The 
configuration file can be made readable by all if desired, but 
this is not necessary for correct operation of the server and is 
not recommended. A sample configuration file \fIsmb.conf.sample
\fRis supplied with the source to the server - this may 
be renamed to \fIsmb.conf\fR and modified to suit 
your needs.
.PP
The remaining notes will assume the following:
.TP 0.2i
\(bu
\fBsmbd\fR (the server program) 
installed in \fI/usr/local/samba/bin\fR
.TP 0.2i
\(bu
\fIsmb.conf\fR (the configuration 
file) installed in \fI/usr/local/samba/lib\fR
.TP 0.2i
\(bu
log files stored in \fI/var/adm/smblogs
\fR.PP
The server may be run either as a daemon by users 
or at startup, or it may be run from a meta-daemon such as 
\fBinetd\fR upon request. If run as a daemon, 
the server will always be ready, so starting sessions will be
faster. If run from a meta-daemon some memory will be saved and
utilities such as the tcpd TCP-wrapper may be used for extra 
security. For serious use as file server it is recommended 
that \fBsmbd\fR be run as a daemon.
.PP
.PP
When you've decided, continue with either
.PP
.TP 0.2i
\(bu
RUNNING THE SERVER AS A DAEMON or
.TP 0.2i
\(bu
RUNNING THE SERVER ON REQUEST.
.SH "RUNNING THE SERVER AS A DAEMON"
.PP
To run the server as a daemon from the command 
line, simply put the \fB-D\fR option on the 
command line. There is no need to place an ampersand at 
the end of the command line - the \fB-D\fR 
option causes the server to detach itself from the tty 
anyway.
.PP
Any user can run the server as a daemon (execute 
permissions permitting, of course). This is useful for 
testing purposes, and may even be useful as a temporary 
substitute for something like ftp. When run this way, however, 
the server will only have the privileges of the user who ran 
it.
.PP
To ensure that the server is run as a daemon whenever 
the machine is started, and to ensure that it runs as root 
so that it can serve multiple clients, you will need to modify 
the system startup files. Wherever appropriate (for example, in 
\fI/etc/rc\fR), insert the following line, 
substituting port number, log file location, configuration file 
location and debug level as desired:
.PP
\fB/usr/local/samba/bin/smbd -D -l /var/adm/smblogs/log 
-s /usr/local/samba/lib/smb.conf\fR
.PP
(The above should appear in your initialization script 
as a single line. Depending on your terminal characteristics, 
it may not appear that way in this man page. If the above appears 
as more than one line, please treat any newlines or indentation 
as a single space or TAB character.)
.PP
If the options used at compile time are appropriate for 
your system, all parameters except \fB-D\fR may 
be omitted. See the section OPTIONS above.
.SH "RUNNING THE SERVER ON REQUEST"
.PP
If your system uses a meta-daemon such as \fBinetd
\fR, you can arrange to have the \fBsmbd\fR server started 
whenever a process attempts to connect to it. This requires several 
changes to the startup files on the host machine. If you are 
experimenting as an ordinary user rather than as root, you will 
need the assistance of your system administrator to modify the 
system files.
.PP
You will probably want to set up the NetBIOS name server 
\fBnmbd\fRat
the same time as \fBsmbd\fR. To do this refer to the 
man page for \fBnmbd(8)\fR
.
.PP
First, ensure that a port is configured in the file 
\fI/etc/services\fR. The well-known port 139 
should be used if possible, though any port may be used.
.PP
Ensure that a line similar to the following is in 
\fI/etc/services\fR:
.PP
\fBnetbios-ssn 139/tcp\fR
.PP
Note for NIS/YP users - you may need to rebuild the 
NIS service maps rather than alter your local \fI/etc/services
\fRfile.
.PP
Next, put a suitable line in the file \fI/etc/inetd.conf
\fR(in the unlikely event that you are using a meta-daemon 
other than inetd, you are on your own). Note that the first item 
in this line matches the service name in \fI/etc/services
\fR\&. Substitute appropriate values for your system
in this line (see \fBinetd(8)\fR):
.PP
\fBnetbios-ssn stream tcp nowait root /usr/local/samba/bin/smbd 
-d1 -l/var/adm/smblogs/log -s/usr/local/samba/lib/smb.conf\fR
.PP
(The above should appear in \fI/etc/inetd.conf\fR 
as a single line. Depending on your terminal characteristics, it may 
not appear that way in this man page. If the above appears as more 
than one line, please treat any newlines or indentation as a single 
space or TAB character.)
.PP
Note that there is no need to specify a port number here, 
even if you are using a non-standard port number.
.PP
Lastly, edit the configuration file to provide suitable 
services. To start with, the following two services should be 
all you need:
.sp
.nf
		[homes]
		writeable = yes

	[printers]
		writeable = no
		printable = yes
		path = /tmp
		public = yes
	
	
.sp
.fi
.PP
This will allow you to connect to your home directory 
and print to any printer supported by the host (user privileges 
permitting).
.SH "PAM INTERACTION"
.PP
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:
.TP 0.2i
\(bu
\fBAccount Validation\fR: 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.
.TP 0.2i
\(bu
\fBSession Management\fR: 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. 
.SH "TESTING THE INSTALLATION"
.PP
If running the server as a daemon, execute it before 
proceeding. If using a meta-daemon, either restart the system 
or kill and restart the meta-daemon. Some versions of 
\fBinetd\fR will reread their configuration
tables if they receive a HUP signal.
.PP
If your machine's name is \fIfred\fR and your 
name is \fImary\fR, you should now be able to connect 
to the service \fI\\\\fred\\mary\fR.
.PP
To properly test and experiment with the server, we 
recommend using the \fBsmbclient\fR program (see 
\fBsmbclient(1)\fR) 
and also going through the steps outlined in the file 
\fIDIAGNOSIS.txt\fR in the \fIdocs/\fR
directory of your Samba installation.
.SH "VERSION"
.PP
This man page is correct for version 2.2 of 
the Samba suite.
.SH "DIAGNOSTICS"
.PP
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.
.PP
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.
.PP
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.
.SH "SIGNALS"
.PP
Sending the \fBsmbd\fR a SIGHUP will cause it to 
reload its \fIsmb.conf\fR configuration 
file within a short period of time.
.PP
To shut down a user's \fBsmbd\fR process it is recommended 
that \fBSIGKILL (-9)\fR \fBNOT\fR 
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 \fBsmbd\fR is to send it a SIGTERM (-15) signal and wait for 
it to die on its own.
.PP
The debug log level of \fBsmbd\fR may be raised
or lowered using \fBsmbcontrol(1)
\fRprogram (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.
.PP
Note that as the signal handlers send a debug write, 
they are not re-entrant in \fBsmbd\fR. This you should wait until 
\fBsmbd\fR 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.
.SH "SEE ALSO"
.PP
hosts_access(5), \fBinetd(8)\fR, 
\fBnmbd(8)\fR, 
\fIsmb.conf(5)\fR
, \fBsmbclient(1)
\fR, and the Internet RFC's
\fIrfc1001.txt\fR, \fIrfc1002.txt\fR. 
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/>.
.SH "AUTHOR"
.PP
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.
.PP
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