From Linux Man Pages
smbd - server to provide SMB/CIFS services to clients
SYNOPSIS
smbd [-D] [-F] [-S] [-i] [-h] [-V] [-b] [-d<debuglevel>] [-l<logdirectory>] [-p<portnumber(s)>] [-O<socketop-
tion>] [-s<configurationfile>]
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 LanMan-
ager 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 configura-
tion file controlling the attributes of those services (see smb.conf(5). This man page will not describe the ser-
vices, 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 con-
nections to any service that is already established. Either the user will have to disconnect from the service, or
smbd killed and restarted.
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. 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 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 If specified, this parameter causes smbd to log to standard output rather than a file.
-i 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 deamon mode
when run from the command line. smbd also logs to standard output, as if the -S parameter had been given.
-V Prints the program version number.
-s <configuration file>
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 for more information. The default configuration file name
is determined at compile time.
-d|--debuglevel=level
level 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
parameter in the smb.conf file.
-l|--logfile=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.
-h|--help
Print a summary of command line options.
-b Prints information about how Samba was built.
-p <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 smb.conf
The default ports are 139 (used for SMB over NetBIOS over TCP) and port 445 (used for plain SMB over TCP).
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., net-
bios-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, how-
ever.
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 limi-
tations of the SMB protocol and the obey pam restrictions smb.conf(5) paramater. 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 vaild, not
disabled and is permitted to login at this time. This also applies to encrypted logins.
•
Session Management: 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 configura-
tion files may need a line added for session support.
VERSION
This man page is correct for version 3.0 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 com-
pile 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 prob-
lems, 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
connections.tdb
share connections (used to enforce max connections, etc...)
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)
sessionid.tdb
session information (e.g. support for 'utmp = yes')
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 nor-
mally 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 per-
formance.
RELATED
hosts_access(5), inetd(8), nmbd(8), smb.conf(5), smbclient(1), testparm(1), testprns(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 http://samba.org/cifs/.
CATEGORY