If you have an outside user that needs to download or upload a file to our site, it's better not to give the person a network account, as the principle of least privilege applies. So we can provide 'anonymous' access to our site via a chrooted user account. It is protected by rssh to only allow SFTP (no SSH shell) and because it is chrooted to its home directory, the remote user will not have access to any other files on our network.
The remote user should use their preferred SFTP client to connect; you should contact help@sbgrid.org for the required username and password.
Once connected, the user can place files into the UPLOADS directory, where you can copy the files out of later. Should the remote user need to download files, you can place them in the DOWNLOADS folder for them to access.