HPNSFTP-SERVER(8)

NAME
hpnsftp-server - HPN/OpenSSH SFTP server subsystem

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

DESCRIPTION
hpnsftp-server is a program that speaks the server side of SFTP protocol to stdout and expects client requests from stdin. hpnsftp-server is not intended to be called directly, but from hpnsshd(8) using the Subsystem option. Command-line flags to hpnsftp-server should be specified in the Subsystem declaration. See hpnsshd_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 hpnsftp-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 . The possible values are: DAEMON, USER, AUTH, LOCAL0, LOCAL1, LOCAL2, LOCAL3, LOCAL4, LOCAL5, LOCAL6, LOCAL7. The default is AUTH.

-h  Displays hpnsftp-server usage information.

-l log_level
    Specifies which messages will be logged by . The possible values are: QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2, and DEBUG3. INFO and VERBOSE log transactions that hpnsftp-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. hpnsftp-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 . 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 hpnsftp-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, hpnsftp-server must be able to access /dev/log for logging to work, and use of hpnsftp-server in a chroot configuration therefore requires that syslogd(8) establish a logging socket inside the chroot directory.

SEE ALSO
hpnsftp(1), hpnssh(1), hpnsshd_config(5), hpnsshd(8) S. Lehtinen and T. Ylonen, SSH File Transfer Protocol, draft-ietf-secsh-filexfer-02.txt, October 2001, work in progress material.

HISTORY
hpnsftp-server first appeared in OpenBSD 2.8 .

AUTHORS
Markus Friedl <Mt markus@openbsd.org>