smbd

Name

smbd — server to provide SMB/CIFS services to clients

Synopsis

smbd [-D] [-F] [-S] [-i] [-h] [-V] [-b] [-d <debug level>] [-l <log directory>] [-p <port number>] [-O <socket option>] [-s <configuration file>]

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

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|--debug=debuglevel

debuglevel 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 log level parameter -in the smb.conf file.

-l|--logfile=logbasename

File name for log/debug files. The extension -".client" will be appended. 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.

-l <log directory>

If specified, - log directory - specifies a log directory into which the "log.smbd" log - file will be created for informational and debug - messages from the running server. The log - file generated is never removed by the server although - its size may be controlled by the - max log size - option in the smb.conf(5) file. Beware: - If the directory specified does not exist, smbd - will log to the default debug log location defined at compile time. -

The default log directory is specified at - compile time.

-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 - SMB over TCP 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.

In order for the server to be useful by most - clients, should you configure it on a port other - than 139, you will require port redirection services - on port 139, details of which are outlined in rfc1002.txt - section 4.3.5.

This parameter is not normally specified except - in the above situation.

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) 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 configuration 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 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.

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.

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.