sftp-server(8) — Linux manual page


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

NAME         top

     sftp-server — OpenSSH SFTP server subsystem

SYNOPSIS         top

     sftp-server [-ehR] [-d start_directory] [-f log_facility]
                 [-l log_level] [-P denied_requests]
                 [-p allowed_requests] [-u umask]
     sftp-server -Q protocol_feature

DESCRIPTION         top

     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
             pathname may contain the following tokens that are expanded
             at runtime: %% 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

     -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:
             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 possible 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 denied_requests
             Specifies a comma-separated list of SFTP protocol requests
             that are banned by the server.  sftp-server will reply to
             any denied request with a failure.  The -Q flag can be used
             to determine the supported request types.  If both denied
             and allowed lists are specified, then the denied list is
             applied before the allowed list.

     -p allowed_requests
             Specifies a comma-separated list of SFTP protocol requests
             that are permitted by the server.  All request types that
             are not on the allowed list 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
             Queries protocol features supported by sftp-server.  At
             present the only feature that may be queried is “requests”,
             which may be used to deny or allow specific requests (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

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

     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         top

     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         top

     sftp-server first appeared in OpenBSD 2.8.

AUTHORS         top

     Markus Friedl <markus@openbsd.org>

COLOPHON         top

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BSD                           July 27, 2021                          BSD