Basic Sandboxing

The simplest form of sandboxing can be set up using the --sandbox-dir command line parameter. This will restrict users accessing the server into the specified directory.


Without sandboxing, a transfer of /file.txt will be stored in /file.txt.

With sandboxing specified, all files in transfers will be prefixed with the sandbox path. For example, if --sandbox-dir is set to /storage, a transfer of /file.txt will be stored in /storage/file.txt. For more details on path processing, please refer to Where Do Transfers Go?.

If you wish to sandbox users to their individual directories, insert a username placeholder %u in the path. The placeholder will then be replaced by each user’s username on the fly. For more information, refer to sandboxing placeholders documentation.


If you start the server with --sandbox-dir set to /home/%u, each user will be sandboxed into their own home directory.

When userA logs in, they will be able to only see files in /home/userA, and the user will perceive this directory as their root directory. Similarly, userB will be locked into /home/userB.


The sandbox directory path (including any placeholders such as %u, if specified) must exist before users can transfer files.