smbd
8
Samba
System Administration tools
4.7
smbd
server to provide SMB/CIFS services to clients
smbd
-D|--daemon
-F|--foreground
-S|--log-stdout
-i|--interactive
-V
-b|--build-options
-d <debug level>
-l|--log-basename <log directory>
-p <port number(s)>
-P <profiling level>
-s <configuration file>
--no-process-group
DESCRIPTION
This program is part of the samba
7 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 manual page 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|--daemon
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.
-F|--foreground
If specified, this parameter causes
the main smbd process to not daemonize,
i.e. double-fork and disassociate with the terminal.
Child processes are still created as normal to service
each connection request, but the main process does not
exit. This operation mode is suitable for running
smbd under process supervisors such
as supervise and svscan
from Daniel J. Bernstein's daemontools
package, or the AIX process monitor.
-S|--log-stdout
If specified, this parameter causes
smbd to log to standard output rather
than a file.
-i|--interactive
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 daemon mode when run from the
command line. smbd will only accept one
connection and terminate. It will also log to standard output,
as if the -S parameter had been given.
&stdarg.server.debug;
&popt.common.samba;
&popt.autohelp;
--no-process-group
Do not create a new process group for smbd.
-b|--build-options
Prints information about how
Samba was built.
-p|--port<port number(s)>
port number(s) is a
space or comma-separated list of TCP ports smbd should listen on.
The default value is taken from the parameter in &smb.conf;
The default ports are 139 (used for SMB over NetBIOS over TCP)
and port 445 (used for plain SMB over TCP).
-P|--profiling-level<profiling level>
profiling level is a
number specifying the level of profiling data to be collected.
0 turns off profiling, 1 turns on counter profiling only,
2 turns on complete profiling, and 3 resets all profiling data.
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.
/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.
/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).
/usr/local/samba/lib/smb.conf
This is the default location of the smb.conf
5 server configuration file. Other common places that systems
install this file are /usr/samba/lib/smb.conf
and /etc/samba/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 smb.conf
5 parameter. When this is set, the following restrictions apply:
Account Validation: All accesses to a
samba server are checked
against PAM to see if the account is valid, not disabled and is permitted to
login at this time. This also applies to encrypted logins.
Session Management: When not using share
level security, users must pass PAM's session checks before access
is granted. Note however, that this is bypassed in share level security.
Note also that some older pam configuration files may need a line
added for session support.
VERSION
This man page is correct for version 3 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 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.
TDB FILES
Samba stores it's data in several TDB (Trivial Database) files, usually located in /var/lib/samba.
(*) information persistent across restarts (but not
necessarily important to backup).
account_policy.tdb*
NT account policy settings such as pw expiration, etc...
brlock.tdb
byte range locks
browse.dat
browse lists
gencache.tdb
generic caching db
group_mapping.tdb*
group mapping information
locking.tdb
share modes & oplocks
login_cache.tdb*
bad pw attempts
messages.tdb
Samba messaging system
netsamlogon_cache.tdb*
cache of user net_info_3 struct from net_samlogon() request (as a domain member)
ntdrivers.tdb*
installed printer drivers
ntforms.tdb*
installed printer forms
ntprinters.tdb*
installed printer information
printing/
directory containing tdb per print queue of cached lpq output
registry.tdb
Windows registry skeleton (connect via regedit.exe)
smbXsrv_session_global.tdb
session information (e.g. support for 'utmp = yes')
smbXsrv_tcon_global.tdb
share connections (used to enforce max connections, etc...)
smbXsrv_open_global.tdb
open file handles (used durable handles, etc...)
share_info.tdb*
share acls
winbindd_cache.tdb
winbindd's cache of user lists, etc...
winbindd_idmap.tdb*
winbindd's local idmap db
wins.dat*
wins database when 'wins support = yes'
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 since 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, testparm
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
https://www.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/) and updated for the Samba 2.0
release by Jeremy Allison. The conversion to DocBook for
Samba 2.2 was done by Gerald Carter. The conversion to DocBook XML 4.2 for
Samba 3.0 was done by Alexander Bokovoy.