SMBD(8)SMBD(8)NAMEsmbd - provide SMB (aka LanManager) services to clients
SYNOPSISsmbd [ -D ] [ -a ] [ -d debuglevel ] [ -l log file ] [ -p port number ]
[ -O socket options ] [ -s configuration file ]
DESCRIPTION
This program is part of the Samba suite.
smbd is a server that can provide most SMB services. The server
provides filespace and printer services to clients using the SMB
protocol. This is compatible with the LanManager protocol, and can
service LanManager clients.
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 smb.conf(5) 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 are closed, the copy of the server for
that client terminates.
The configuration file is automatically reloaded if it changes. You can
force a reload by sending a SIGHUP to the server.
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.
By default, the server will NOT operate as a daemon.
-a
If this parameter is specified, the log files will be overwritten
with each new connection. By default, the log files will be appended
to.
-d debuglevel
debuglevel is an integer from 0 to 5.
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.
-l log file
If specified, logfile specifies a base filename into which
operational data from the running server will be logged.
The default base name is specified at compile time.
The base name is used to generate actual log file names. For
example, if the name specified was "log", the following files would
be used for log data:
log.debug (containing debugging information)
log.in (containing inbound transaction data)
log.out (containing outbound transaction data)
The log files generated are never removed by the server.
-O socket options
See the socket options section of smb.conf(5) 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 server 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.
This parameter is not normally specified except in the above
situation.
-s configuration file
The default configuration file name is determined at compile time.
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.
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
section "INSTALLATION" below.
/etc/rc
(or whatever initialisation 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.
/etc/services
If running the server via the meta-daemon inetd, this file must
contain a mapping of service name (eg., netbios-ssn) to service
port (eg., 139) and protocol type (eg., tcp). See the section
"INSTALLATION" below.
/usr/local/samba/lib/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.
INSTALLATION
The location of the server and its support files is a matter for
individual system administrators. The following are thus suggestions
only.
It is recommended that the server software be installed under the
/usr/local/samba 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 smbd 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 smbd file setgid to an empty group may prevent this hole
from being exploited. This secrity hole and the suggested fix has only
been confirmed on 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.
The server log files should be put in a directory readable and writable
only by root, as the log files may contain sensitive information.
The configuration file should be placed in a directory readable and
writable 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 "smb.conf.sample" is supplied with the source to the server - this
may be renamed to "smb.conf" and modified to suit your needs.
The remaining notes will assume the following:
smbd (the server program) installed in /usr/local/samba/bin
smb.conf (the configuration file) installed in /usr/local/samba/lib
log files stored in /var/adm/smblogs
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 inetd 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.
When you've decided, continue with either "RUNNING THE SERVER AS A
DAEMON" or "RUNNING THE SERVER ON REQUEST".
RUNNING THE SERVER AS A DAEMON
To run the server as a daemon from the command line, simply put the -D
option on the command line. There is no need to place an ampersand at
the end of the command line - the -D option causes the server to detach
itself from the tty anyway.
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.
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 /etc/rc), insert the following
line, substituting port number, log file location, configuration file
location and debug level as desired:
/usr/local/samba/bin/smbd -D-l /var/adm/smblogs/log -s
/usr/local/samba/lib/smb.conf
(The above should appear in your initialisation 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.)
If the options used at compile time are appropriate for your system,
all parameters except the desired debug level and -D may be omitted.
See the section "OPTIONS" above.
RUNNING THE SERVER ON REQUEST
If your system uses a meta-daemon such as inetd, you can arrange to
have the smbd 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.
You will probably want to set up the name server nmbd at the same time
as smbd - refer to the man page nmbd(8).
First, ensure that a port is configured in the file /etc/services. The
well-known port 139 should be used if possible, though any port may be
used.
Ensure that a line similar to the following is in /etc/services:
netbios-ssn 139/tcp
Note for NIS/YP users - you may need to rebuild the NIS service maps
rather than alter your local /etc/services file.
Next, put a suitable line in the file /etc/inetd.conf (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 /etc/services. Substitute appropriate values for your system
in this line (see inetd(8)):
netbios-ssn stream tcp nowait root /usr/local/samba/bin/smbd -d1
-l/var/adm/smblogs/log -s/usr/local/samba/lib/smb.conf
(The above should appear in /etc/inetd.conf 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.)
Note that there is no need to specify a port number here, even if you
are using a non-standard port number.
Lastly, edit the configuration file to provide suitable services. To
start with, the following two services should be all you need:
[homes]
writable = yes
[printers]
writable = no
printable = yes
path = /tmp
public = yes
This will allow you to connect to your home directory and print to any
printer supported by the host (user privileges permitting).
TESTING THE INSTALLATION
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 inetd will reread their configuration
tables if they receive a HUP signal.
If your machine's name is "fred" and your name is "mary", you should
now be able to connect to the service "\\fred\mary".
To properly test and experiment with the server, we recommend using the
smbclient program (see smbclient(1)).
VERSION
This man page is (mostly) correct for version 1.9.00 of the Samba
suite, plus some of the recent patches to it. These notes will
necessarily lag behind development of the software, so it is possible
that your version of the server has extensions or parameter semantics
that differ from or are not covered by this man page. Please notify
these to the address below for rectification.
SEE ALSOhosts_access(5), inetd(8), nmbd(8), smb.conf(5), smbclient(1),
testparm(1), testprns(1)DIAGNOSTICS
[This section under construction]
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 time
of creation of this man page the source code is still too fluid 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.
BUGS
None known.
CREDITS
The original Samba software and related utilities were created by
Andrew Tridgell (samba-bugs@samba.anu.edu.au). Andrew is also the
Keeper of the Source for this project.
See smb.conf(5) for a full list of contributors and details on how to
submit bug reports, comments etc.
smbdsmbdSMBD(8)
