SFTPGo

Fully featured and highly configurable SFTP server with optional FTP/S and WebDAV support, written in Go. It can serve local filesystem, S3 or Google Cloud Storage.

Features

• SFTPGo uses virtual accounts stored inside a "data provider".
• SQLite, MySQL, PostgreSQL, bbolt (key/value store in pure Go) and in-memory data providers are supported.
• Each account is chrooted to its home directory.
• Public key and password authentication. Multiple public keys per user are supported.
• SSH user certificate authentication.
• Keyboard interactive authentication. You can easily setup a customizable multi-factor authentication.
• Partial authentication. You can configure multi-step authentication requiring, for example, the user password after successful public key authentication.
• Per user authentication methods. You can configure the allowed authentication methods for each user.
• Custom authentication via external programs/HTTP API is supported.
• Dynamic user modification before login via external programs/HTTP API is supported.
• Quota support: accounts can have individual quota expressed as max total size and/or max number of files.
• Bandwidth throttling is supported, with distinct settings for upload and download.
• Per user maximum concurrent sessions.
• Per user and per directory permission management: list directory contents, upload, overwrite, download, delete, rename, create directories, create symlinks, change owner/group and mode, change access and modification times.
• Per user files/folders ownership mapping: you can map all the users to the system account that runs SFTPGo (all platforms are supported) or you can run SFTPGo as root user and map each user or group of users to a different system account (*NIX only).
• Per user IP filters are supported: login can be restricted to specific ranges of IP addresses or to a specific IP address.
• Per user and per directory file extensions filters are supported: files can be allowed or denied based on their extensions.
• Virtual folders are supported: directories outside the user home directory can be exposed as virtual folders.
• Configurable custom commands and/or HTTP notifications on file upload, download, pre-delete, delete, rename, on SSH commands and on user add, update and delete.
• Automatically terminating idle connections.
• Atomic uploads are configurable.
• Support for Git repositories over SSH.
• SCP and rsync are supported.
• FTP/S is supported.
• WebDAV is supported.
• Support for serving local filesystem, S3 Compatible Object Storage and Google Cloud Storage over SFTP/SCP/FTP/WebDAV.
• Prometheus metrics are exposed.
• Support for HAProxy PROXY protocol: you can proxy and/or load balance the SFTP/SCP/FTP/WebDAV service without losing the information about the client's address.
• REST API for users and folders management, backup, restore and real time reports of the active connections with possibility of forcibly closing a connection.
• Web based administration interface to easily manage users, folders and connections.
• Easy migration from Linux system user accounts.
• Portable mode: a convenient way to share a single directory on demand.
• Performance analysis using built-in profiler.
• Configuration format is at your choice: JSON, TOML, YAML, HCL, envfile are supported.
• Log files are accurate and they are saved in the easily parsable JSON format (more information).

Platforms

SFTPGo is developed and tested on Linux. After each commit, the code is automatically built and tested on Linux, macOS and Windows using a GitHub Action. The test cases are regularly manually executed and passed on FreeBSD. Other *BSD variants should work too.

Requirements

• Go 1.13 or higher as build only dependency.
• A suitable SQL server to use as data provider: PostgreSQL 9.4+ or MySQL 5.6+ or SQLite 3.x.
• The SQL server is optional: you can choose to use an embedded bolt database as key/value store or an in memory data provider.

Installation

Binary releases for Linux, macOS, and Windows are available. Please visit the releases page.

Sample Dockerfiles for Debian and Alpine are available inside the source tree docker directory.

Some Linux distro packages are available:

• For Arch Linux via AUR:
  • sftpgo. This package follows stable releases. It requires git, gcc and go to build.
  • sftpgo-bin. This package follows stable releases downloading the prebuilt linux binary from GitHub. It does not require git, gcc and go to build.
  • sftpgo-git. This package builds and installs the latest git master. It requires git, gcc and go to build.

You can easily test new features selecting a commit from the Actions page and downloading the matching build artifacts for Linux, macOS or Windows. GitHub stores artifacts for 90 days.

Alternately, you can build from source.

Configuration

A full explanation of all configuration methods can be found here.

Please make sure to initialize the data provider before running the daemon!

To start the SFTP server with default settings, simply run:

sftpgo serve

Check out this documentation if you want to run SFTPGo as a service.

Data provider initialization

Before starting the SFTPGo server, please ensure that the configured data provider is properly initialized.

SQL based data providers (SQLite, MySQL, PostgreSQL) require the creation of a database containing the required tables. Memory and bolt data providers do not require an initialization.

After configuring the data provider using the configuration file, you can create the required database structure using the initprovider command. For SQLite provider, the initprovider command will auto create the database file, if missing, and the required tables. For PostgreSQL and MySQL providers, you need to create the configured database, and the initprovider command will create the required tables.

For example, you can simply execute the following command from the configuration directory:

sftpgo initprovider

Take a look at the CLI usage to learn how to specify a different configuration file:

sftpgo initprovider --help

After the initialization, the database structure will be automatically checked and updated, if required, at startup.

Authentication options

External Authentication

Custom authentication methods can easily be added. SFTPGo supports external authentication modules, and writing a new backend can be as simple as a few lines of shell script. More information can be found here.

Keyboard Interactive Authentication

Keyboard interactive authentication is, in general, a series of questions asked by the server with responses provided by the client. This authentication method is typically used for multi-factor authentication.

More information can be found here.

Dynamic user creation or modification

A user can be created or modified by an external program just before the login. More information about this can be found here.

Custom Actions

SFTPGo allows to configure custom commands and/or HTTP notifications on file upload, download, delete, rename, on SSH commands and on user add, update and delete.

More information about custom actions can be found here.

Virtual folders

Directories outside the user home directory can be exposed as virtual folders, more information here.

Storage backends

S3 Compabible Object Storage backends

Each user can be mapped to whole bucket or to a bucket virtual folder. This way, the mapped bucket/virtual folder is exposed over SFTP/SCP. More information about S3 integration can be found here.

Google Cloud Storage backend

Each user can be mapped with a Google Cloud Storage bucket or a bucket virtual folder. This way, the mapped bucket/virtual folder is exposed over SFTP/SCP. More information about Google Cloud Storage integration can be found here.

Other Storage backends

Adding new storage backends is quite easy:

• implement the Fs interface.
• update the user method GetFilesystem to return the new backend
• update the web interface and the REST API CLI
• add the flags for the new storage backed to the portable mode

Anyway, some backends require a pay per use account (or they offer free account for a limited time period only). To be able to add support for such backends or to review pull requests, please provide a test account. The test account must be available for enough time to be able to maintain the backend and do basic tests before each new release.

Brute force protection

The connection failed logs can be used for integration in tools such as Fail2ban. Example of jails and filters working with systemd/journald are available in fail2ban directory.

Account's configuration properties

Details information about account configuration properties can be found here.

Performance

SFTPGo can easily saturate a Gigabit connection on low end hardware with no special configuration, this is generally enough for most use cases.

More in-depth analysis of performance can be found here.

Acknowledgements

SFTPGo makes use of the third party libraries listed inside go.mod. Some code was initially taken from Pterodactyl SFTP Server. We are very grateful to all the people who contributed with ideas and/or pull requests.

License

GNU GPLv3