SFTP-SERVER(8)		  BSD System Manager's Manual		SFTP-SERVER(8)

NAME
     sftp-server -- SFTP server subsystem

SYNOPSIS
     sftp-server [-ehR] [-d start_directory] [-f log_facility] [-l log_level]
		 [-P blacklisted_requests] [-p whitelisted_requests]
		 [-u umask] [-m force_file_perms]
     sftp-server -Q protocol_feature

DESCRIPTION
     sftp-server is a program that speaks the server side of SFTP protocol to
     stdout and expects client requests from stdin.  sftp-server is not
     intended to be called directly, but from sshd(8) using the Subsystem
     option.

     Command-line flags to sftp-server should be specified in the Subsystem
     declaration.  See sshd_config(5) for more information.

     Valid options are:

     -d start_directory
	     specifies an alternate starting directory for users.  The path-
	     name may contain the following tokens that are expanded at run-
	     time: %% is replaced by a literal '%', %d is replaced by the home
	     directory of the user being authenticated, and %u is replaced by
	     the username of that user.	 The default is to use the user's home
	     directory.	 This option is useful in conjunction with the
	     sshd_config(5) ChrootDirectory option.

     -e	     Causes sftp-server to print logging information to stderr instead
	     of syslog for debugging.

     -f log_facility
	     Specifies the facility code that is used when logging messages
	     from sftp-server.	The possible values are: DAEMON, USER, AUTH,
	     LOCAL0, LOCAL1, LOCAL2, LOCAL3, LOCAL4, LOCAL5, LOCAL6, LOCAL7.
	     The default is AUTH.

     -h	     Displays sftp-server usage information.

     -l log_level
	     Specifies which messages will be logged by sftp-server.  The pos-
	     sible values are: QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG,
	     DEBUG1, DEBUG2, and DEBUG3.  INFO and VERBOSE log transactions
	     that sftp-server performs on behalf of the client.	 DEBUG and
	     DEBUG1 are equivalent.  DEBUG2 and DEBUG3 each specify higher
	     levels of debugging output.  The default is ERROR.

     -P blacklisted_requests
	     Specify a comma-separated list of SFTP protocol requests that are
	     banned by the server.  sftp-server will reply to any blacklisted
	     request with a failure.  The -Q flag can be used to determine the
	     supported request types.  If both a blacklist and a whitelist are
	     specified, then the blacklist is applied before the whitelist.

     -p whitelisted_requests
	     Specify a comma-separated list of SFTP protocol requests that are
	     permitted by the server.  All request types that are not on the
	     whitelist will be logged and replied to with a failure message.

	     Care must be taken when using this feature to ensure that
	     requests made implicitly by SFTP clients are permitted.

     -Q protocol_feature
	     Query protocol features supported by sftp-server.	At present the
	     only feature that may be queried is ``requests'', which may be
	     used for black or whitelisting (flags -P and -p respectively).

     -R	     Places this instance of sftp-server into a read-only mode.
	     Attempts to open files for writing, as well as other operations
	     that change the state of the filesystem, will be denied.

     -u umask
	     Sets an explicit umask(2) to be applied to newly-created files
	     and directories, instead of the user's default mask.

     -m force_file_perms
	     Sets explicit file permissions to be applied to newly-created
	     files instead of the default or client requested mode.  Numeric
	     values include: 777, 755, 750, 666, 644, 640, etc.	 Option -u is
	     ineffective if -m is set.

     On some systems, sftp-server must be able to access /dev/log for logging
     to work, and use of sftp-server in a chroot configuration therefore
     requires that syslogd(8) establish a logging socket inside the chroot
     directory.

SEE ALSO
     sftp(1), ssh(1), sshd_config(5), sshd(8)

     T. Ylonen and S. Lehtinen, SSH File Transfer Protocol, draft-ietf-secsh-
     filexfer-02.txt, October 2001, work in progress material.

HISTORY
     sftp-server first appeared in OpenBSD 2.8.

AUTHORS
     Markus Friedl <markus@openbsd.org>

BSD				April 23, 2024				   BSD