NAME

     sftp-server — OpenSSH SFTP server subsystem

SYNOPSIS

     sftp-server [-ehR] [-d start_directory] [-f log_facility] [-l log_level] [-P blacklisted_requests]
                 [-p whitelisted_requests] [-u umask]
     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 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 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 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 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.

     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>