sftp-server — SFTP server subsystem
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
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)
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.
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).
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.
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.
sftp-server first appeared in OpenBSD 2.8.
gsisshd(8), gsisshd_config(5), sftp(1), sshd(8), sshd_config(5).
The man page gsisftp-server(8) is an alias of sftp-server(8).