Tribblix: manual page: samba-smbd.8

SMBD(8) System Administration tools SMBD(8)

NAME

smbd - server to provide SMB/CIFS services to clients

SYNOPSIS

smbd [-D|--daemon] [-i|--interactive] [-F|--foreground]
[--no-process-group] [-b|--build-options] [-p <port number(s)>]
[-P <profiling level>] [-d <debug level>] [--debug-stdout]
[--configfile=<configuration file>] [--option=<name>=<value>]
[-l|--log-basename <log directory>] [--leak-report]
[--leak-report-full] [-V|--version]

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 three minutes, if they change. One 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.

Instead of sending a SIGHUP signal, a request to reload configuration
file may be sent using smbcontrol(1) program.

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.

-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.

-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.

--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 ports
parameter in ${prefix}/etc/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.

-d|--debuglevel=DEBUGLEVEL, --debug-stdout
level is an integer from 0 to 10. The default value if this
parameter is not specified is 0.

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
level parameter in the ${prefix}/etc/smb.conf file. This will
redirect debug output to STDOUT. By default server daemons are
logging to a log file.

--configfile=CONFIGFILE
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 ${prefix}/etc/smb.conf for more information. The default
configuration file name is determined at compile time.

--option=<name>=<value>
Set the smb.conf(5) option "<name>" to value "<value>" from the
command line. This overrides compiled-in defaults and options
read from the configuration file. If a name or a value includes a
space, wrap whole --option=name=value into quotes.

-l|--log-basename=logdirectory
Base directory name for log/debug files. The extension
".progname" will be appended (e.g. log.smbclient, log.smbd,
etc...). The log file is never removed by the client.

--leak-report
Enable talloc leak reporting on exit.

--leak-report-full
Enable full talloc leak reporting on exit.

-V|--version
Prints the program version number.

-?|--help
Print a summary of command line options.

--usage
Display brief usage message.

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 obey pam
restrictions smb.conf(5) parameter. When this is set, the following
restrictions apply:

+o 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.

+o 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 part of version 4.18.11 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.

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.

Samba 4.18.11 03/13/2024 SMBD(8)