======= proftpd ======= For testing proftpd sftp module :: apt install proftpd-basic openssh-client openssh-server Add a local user user :: adduser user Add the following snippet for sftp under /etc/proftpd/conf.d/sftp.conf :: <IfModule mod_sftp.c> SFTPEngine on Port 2222 SFTPLog /var/log/proftpd/sftp.log SFTPHostKey /etc/ssh/ssh_host_rsa_key SFTPAuthMethods publickey password SFTPAuthorizedUserKeys file:/etc/proftpd/authorized_keys/%u RequireValidShell off SFTPCompression delayed </IfModule> restart proftpd :: systemctl restart proftpd Create a RFC4716 key for user user (log as user and if needed create a key by ssh-keygen) :: ssh-keygen -e copy this key to /etc/proftpd/authorized_keys/user test sftp by :: sftp -vvvvv -P 2222 user@localhost