Ubuntu Manpage: smbd - server to provide SMB/CIFS services to clients

Provided by: samba_4.20.4+dfsg-1ubuntu1_amd64

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 /etc/samba/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
/etc/samba/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 /etc/samba/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:

              •   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 part of version 4.20.4-Ubuntu-4.20.4+dfsg-1ubuntu1 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.