sftpgo-mirror/docs/full-configuration.md

Configuring SFTPGo

Command line options

The SFTPGo executable can be used this way:

Usage:
  sftpgo [command]

Available Commands:
  help         Help about any command
  initprovider Initializes the configured data provider
  portable     Serve a single directory
  serve        Start the SFTP Server

Flags:
  -h, --help      help for sftpgo
  -v, --version

 Use "sftpgo [command] --help" for more information about a command

The serve command supports the following flags:

• --config-dir string. Location of the config dir. This directory should contain the configuration file and is used as the base directory for any files that use a relative path (eg. the private keys for the SFTP server, the SQLite or bblot database if you use SQLite or bbolt as data provider). The default value is "." or the value of SFTPGO_CONFIG_DIR environment variable.
• --config-file string. Name of the configuration file. It must be the name of a file stored in config-dir, not the absolute path to the configuration file. The specified file name must have no extension because we automatically append JSON, YAML, TOML, HCL and Java extensions when we search for the file. The default value is "sftpgo" (and therefore sftpgo.json, sftpgo.yaml and so on are searched) or the value of SFTPGO_CONFIG_FILE environment variable.
• --log-compress boolean. Determine if the rotated log files should be compressed using gzip. Default false or the value of SFTPGO_LOG_COMPRESS environment variable (1 or true, 0 or false). It is unused if log-file-path is empty.
• --log-file-path string. Location for the log file, default "sftpgo.log" or the value of SFTPGO_LOG_FILE_PATH environment variable. Leave empty to write logs to the standard error.
• --log-max-age int. Maximum number of days to retain old log files. Default 28 or the value of SFTPGO_LOG_MAX_AGE environment variable. It is unused if log-file-path is empty.
• --log-max-backups int. Maximum number of old log files to retain. Default 5 or the value of SFTPGO_LOG_MAX_BACKUPS environment variable. It is unused if log-file-path is empty.
• --log-max-size int. Maximum size in megabytes of the log file before it gets rotated. Default 10 or the value of SFTPGO_LOG_MAX_SIZE environment variable. It is unused if log-file-path is empty.
• --log-verbose boolean. Enable verbose logs. Default true or the value of SFTPGO_LOG_VERBOSE environment variable (1 or true, 0 or false).

If you don't configure any private host key, the daemon will use id_rsa and id_ecdsa in the configuration directory. If these files don't exist, the daemon will attempt to autogenerate them (if the user that executes SFTPGo has write access to the config-dir). The server supports any private key format supported by crypto/ssh.

Configuration file

The configuration file contains the following sections:

• "sftpd", the configuration for the SFTP server
  • bind_port, integer. The port used for serving SFTP requests. Default: 2022
  • bind_address, string. Leave blank to listen on all available network interfaces. Default: ""
  • idle_timeout, integer. Time in minutes after which an idle client will be disconnected. 0 means disabled. Default: 15
  • max_auth_tries integer. Maximum number of authentication attempts permitted per connection. If set to a negative number, the number of attempts is unlimited. If set to zero, the number of attempts are limited to 6.
  • umask, string. Umask for the new files and directories. This setting has no effect on Windows. Default: "0022"
  • banner, string. Identification string used by the server. Leave empty to use the default banner. Default SFTPGo_<version>, for example SSH-2.0-SFTPGo_0.9.5
  • upload_mode integer. 0 means standard: the files are uploaded directly to the requested path. 1 means atomic: files are uploaded to a temporary path and renamed to the requested path when the client ends the upload. Atomic mode avoids problems such as a web server that serves partial files when the files are being uploaded. In atomic mode, if there is an upload error, the temporary file is deleted and so the requested upload path will not contain a partial file. 2 means atomic with resume support: same as atomic but if there is an upload error, the temporary file is renamed to the requested path and not deleted. This way, a client can reconnect and resume the upload.
  • actions, struct. It contains the command to execute and/or the HTTP URL to notify and the trigger conditions. See the "Custom Actions" paragraph for more details
    • execute_on, list of strings. Valid values are download, upload, delete, rename, ssh_cmd. Leave empty to disable actions.
    • command, string. Absolute path to the command to execute. Leave empty to disable.
    • http_notification_url, a valid URL. An HTTP GET request will be executed to this URL. Leave empty to disable.
  • keys, struct array. It contains the daemon's private keys. If empty or missing, the daemon will search or try to generate id_rsa and id_ecdsa keys in the configuration directory.
    • private_key, path to the private key file. It can be a path relative to the config dir or an absolute one.
  • kex_algorithms, list of strings. Available KEX (Key Exchange) algorithms in preference order. Leave empty to use default values. The supported values can be found here: crypto/ssh
  • ciphers, list of strings. Allowed ciphers. Leave empty to use default values. The supported values can be found here: crypto/ssh
  • macs, list of strings. Available MAC (message authentication code) algorithms in preference order. Leave empty to use default values. The supported values can be found here: crypto/ssh
  • trusted_user_ca_keys, list of public keys paths of certificate authorities that are trusted to sign user certificates for authentication. The paths can be absolute or relative to the configuration directory.
  • login_banner_file, path to the login banner file. The contents of the specified file, if any, are sent to the remote user before authentication is allowed. It can be a path relative to the config dir or an absolute one. Leave empty to disable login banner.
  • setstat_mode, integer. 0 means "normal mode": requests for changing permissions, owner/group and access/modification times are executed. 1 means "ignore mode": requests for changing permissions, owner/group and access/modification times are silently ignored.
  • enabled_ssh_commands, list of enabled SSH commands. These SSH commands are enabled by default: md5sum, sha1sum, cd, pwd, scp. * enables all supported commands. Some commands are implemented directly inside SFTPGo, while for other commands we use system commands that need to be installed and in your system's PATH. For system commands we have no direct control on file creation/deletion and so we cannot support virtual folders, cloud storage filesystem, such as S3, and quota check is suboptimal: if quota is enabled, the number of files is checked at the command start and not while new files are created. The allowed size is calculated as the difference between the max quota and the used one, and it is checked against the bytes transferred via SSH. The command is aborted if it uploads more bytes than the remaining allowed size calculated at the command start. Anyway, we see the bytes that the remote command sends to the local command via SSH. These bytes contain both protocol commands and files, and so the size of the files is different from the size trasferred via SSH: for example, a command can send compressed files, or a protocol command (few bytes) could delete a big file. To mitigate this issue, quotas are recalculated at the command end with a full home directory scan. This could be heavy for big directories. If you need system commands and quotas you could consider disabling quota restrictions and periodically update quota usage yourself using the REST API. We support the following SSH commands:
    • scp, we have our own SCP implementation since we can't rely on scp system command to proper handle quotas, user's home dir restrictions, cloud storage providers and virtual folders. SCP between two remote hosts is supported using the -3 scp option.
    • md5sum, sha1sum, sha256sum, sha384sum, sha512sum. Useful to check message digests for uploaded files. These commands are implemented inside SFTPGo so they work even if the matching system commands are not available, for example, on Windows.
    • cd, pwd. Some SFTP clients do not support the SFTP SSH_FXP_REALPATH packet type, so they use cd and pwd SSH commands to get the initial directory. Currently cd does nothing and pwd always returns the / path.
    • git-receive-pack, git-upload-pack, git-upload-archive. These commands enable support for Git repositories over SSH. They need to be installed and in your system's PATH. Git commands are not allowed inside virtual folders or inside directories with file extensions filters.
    • rsync. The rsync command needs to be installed and in your system's PATH. We cannot avoid that rsync creates symlinks, so if the user has the permission to create symlinks, we add the option --safe-links to the received rsync command if it is not already set. This should prevent creating symlinks that point outside the home dir. If the user cannot create symlinks, we add the option --munge-links if it is not already set. This should make symlinks unusable (but manually recoverable). The rsync command interacts with the filesystem directly and it is not aware of virtual folders and file extensions filters, so it will be automatically disabled for users with these features enabled.
  • keyboard_interactive_auth_program, string. Deprecated, please use keyboard_interactive_auth_hook.
  • keyboard_interactive_auth_hook, string. Absolute path to an external program or an HTTP URL to invoke for keyboard interactive authentication. See the "Keyboard Interactive Authentication" paragraph for more details.
  • proxy_protocol, integer. Support for HAProxy PROXY protocol. If you are running SFTPGo behind a proxy server such as HAProxy, AWS ELB or NGNIX, you can enable the proxy protocol. It provides a convenient way to safely transport connection information such as a client's address across multiple layers of NAT or TCP proxies to get the real client IP address instead of the proxy IP. Both protocol versions 1 and 2 are supported. If the proxy protocol is enabled in SFTPGo then you have to enable the protocol in your proxy configuration too. For example, for HAProxy, add send-proxy or send-proxy-v2 to each server configuration line. The following modes are supported:
    • 0, disabled
    • 1, enabled. Proxy header will be used and requests without proxy header will be accepted
    • 2, required. Proxy header will be used and requests without proxy header will be rejected
  • proxy_allowed, List of IP addresses and IP ranges allowed to send the proxy header:
    • If proxy_protocol is set to 1 and we receive a proxy header from an IP that is not in the list then the connection will be accepted and the header will be ignored
    • If proxy_protocol is set to 2 and we receive a proxy header from an IP that is not in the list then the connection will be rejected
• "data_provider", the configuration for the data provider
  • driver, string. Supported drivers are sqlite, mysql, postgresql, bolt, memory
  • name, string. Database name. For driver sqlite this can be the database name relative to the config dir or the absolute path to the SQLite database. For driver memory this is the (optional) path relative to the config dir or the absolute path to the users dump, obtained using the dumpdata REST API, to load. This dump will be loaded at startup and can be reloaded on demand sending a SIGHUP signal on Unix based systems and a paramchange request to the running service on Windows. The memory provider will not modify the provided file so quota usage and last login will not be persisted
  • host, string. Database host. Leave empty for drivers sqlite, bolt and memory
  • port, integer. Database port. Leave empty for drivers sqlite, bolt and memory
  • username, string. Database user. Leave empty for drivers sqlite, bolt and memory
  • password, string. Database password. Leave empty for drivers sqlite, bolt and memory
  • sslmode, integer. Used for drivers mysql and postgresql. 0 disable SSL/TLS connections, 1 require ssl, 2 set ssl mode to verify-ca for driver postgresql and skip-verify for driver mysql, 3 set ssl mode to verify-full for driver postgresql and preferred for driver mysql
  • connectionstring, string. Provide a custom database connection string. If not empty, this connection string will be used instead of building one using the previous parameters. Leave empty for drivers bolt and memory
  • users_table, string. Database table for SFTP users
  • manage_users, integer. Set to 0 to disable users management, 1 to enable
  • track_quota, integer. Set the preferred mode to track users quota between the following choices:
    • 0, disable quota tracking. REST API to scan user dir and update quota will do nothing
    • 1, quota is updated each time a user uploads or deletes a file, even if the user has no quota restrictions
    • 2, quota is updated each time a user uploads or deletes a file, but only for users with quota restrictions. With this configuration, the "quota scan" REST API can still be used to periodically update space usage for users without quota restrictions
  • pool_size, integer. Sets the maximum number of open connections for mysql and postgresql driver. Default 0 (unlimited)
  • users_base_dir, string. Users default base directory. If no home dir is defined while adding a new user, and this value is a valid absolute path, then the user home dir will be automatically defined as the path obtained joining the base dir and the username
  • actions, struct. It contains the command to execute and/or the HTTP URL to notify and the trigger conditions. See the "Custom Actions" paragraph for more details
    • execute_on, list of strings. Valid values are add, update, delete. update action will not be fired for internal updates such as the last login or the user quota fields.
    • command, string. Absolute path to the command to execute. Leave empty to disable.
    • http_notification_url, a valid URL. Leave empty to disable.
  • external_auth_program, string. Deprecated, please use external_auth_hook.
  • external_auth_hook, string. Absolute path to an external program or an HTTP URL to invoke for users authentication. See the "External Authentication" paragraph for more details. Leave empty to disable.
  • external_auth_scope, integer. 0 means all supported authetication scopes (passwords, public keys and keyboard interactive). 1 means passwords only. 2 means public keys only. 4 means key keyboard interactive only. The flags can be combined, for example 6 means public keys and keyboard interactive
  • credentials_path, string. It defines the directory for storing user provided credential files such as Google Cloud Storage credentials. This can be an absolute path or a path relative to the config dir
  • pre_login_program, string. Deprecated, please use pre_login_hook.
  • pre_login_hook, string. Absolute path to an external program or an HTTP URL to invoke to modify user details just before the login. See the "Dynamic user modification" paragraph for more details. Leave empty to disable.
• "httpd", the configuration for the HTTP server used to serve REST API and to expose the built-in web interface
  • bind_port, integer. The port used for serving HTTP requests. Set to 0 to disable HTTP server. Default: 8080
  • bind_address, string. Leave blank to listen on all available network interfaces. Default: "127.0.0.1"
  • templates_path, string. Path to the HTML web templates. This can be an absolute path or a path relative to the config dir
  • static_files_path, string. Path to the static files for the web interface. This can be an absolute path or a path relative to the config dir
  • backups_path, string. Path to the backup directory. This can be an absolute path or a path relative to the config dir. We don't allow backups in arbitrary paths for security reasons
  • auth_user_file, string. Path to a file used to store usernames and passwords for basic authentication. This can be an absolute path or a path relative to the config dir. We support HTTP basic authentication, and the file format must conform to the one generated using the Apache htpasswd tool. The supported password formats are bcrypt ($2y$ prefix) and md5 crypt ($apr1$ prefix). If empty, HTTP authentication is disabled.
  • certificate_file, string. Certificate for HTTPS. This can be an absolute path or a path relative to the config dir.
  • certificate_key_file, string. Private key matching the above certificate. This can be an absolute path or a path relative to the config dir. If both the certificate and the private key are provided, the server will expect HTTPS connections. Certificate and key files can be reloaded on demand sending a SIGHUP signal on Unix based systems and a paramchange request to the running service on Windows.
• "http", the configuration for HTTP clients. HTTP clients are used for executing hooks such as the ones used for custom actions, external authentication and pre-login user modifications
  • timeout, integer. Timeout specifies a time limit, in seconds, for requests.
  • ca_certificates, list of strings. List of paths to extra CA certificates to trust. The paths can be absolute or relative to the config dir. Adding trusted CA certificates is a convenient way to use self-signed certificates without defeating the purpose of using TLS.
  • skip_tls_verify, boolean. if enabled the HTTP client accepts any TLS certificate presented by the server and any host name in that certificate. In this mode, TLS is susceptible to man-in-the-middle attacks. This should be used only for testing.

A full example showing the default config (in JSON format) can be found here.

If you want to use a private key that use an algorithm different from RSA or ECDSA, or more private keys, then generate your own keys and replace the empty keys array with something like this:

"keys": [
  {
    "private_key": "id_rsa"
  },
  {
    "private_key": "id_ecdsa"
  },
  {
    "private_key": "id_ed25519"
  }
]

where id_rsa, id_ecdsa and id_ed25519 in this example are files containing your generated keys. You can use absolute paths or paths relative to the configuration directory.

The configuration can be read from JSON, TOML, YAML, HCL, envfile and Java properties config files. If your config-file flag is set to sftpgo (default value), you need to create a configuration file called sftpgo.json or sftpgo.yaml and so on inside config-dir.

Environment variables

You can also override all the available configuration options using environment variables. SFTPGo will check for environment variables with a name matching the key uppercased and prefixed with the SFTPGO_. You need to use __ to traverse a struct.

Let's see some examples:

• To set sftpd bind_port, you need to define the env var SFTPGO_SFTPD__BIND_PORT
• To set the execute_on actions, you need to define the env var SFTPGO_SFTPD__ACTIONS__EXECUTE_ON. For example SFTPGO_SFTPD__ACTIONS__EXECUTE_ON=upload,download

Please note that, to override configuration options with environment variables, a configuration file containing the options to override is required. You can, for example, deploy the default configuration file and then override the options you need to customize using environment variables.