Current File : //etc/proftpd/tls.conf

<IfModule mod_tls.c>
    TLSEngine                   on
    TLSLog                      /var/log/proftpd/tls.log

    TLSProtocol                 ALL -SSLv3 -TLSv1 -TLSv1.1 
    TLSCipherSuite              ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384

    TLSRSACertificateFile       /etc/ssl/keyhelp/ftp.pem
    TLSRSACertificateKeyFile    /etc/ssl/keyhelp/ftp.pem
    TLSCACertificateFile        /etc/ssl/keyhelp/ftp-ca.crt

    TLSOptions                  NoSessionReuseRequired

    TLSVerifyClient             off

    # Are clients required to use FTP over TLS when talking to this server?
    TLSRequired                 on

    # Allow SSL/TLS renegotiations when the client requests them, but
    # do not force the renegotations. Some clients do not support
    # SSL/TLS renegotiations; when mod_tls forces a renegotiation, these
    # clients will close the data connection, or there will be a timeout
    # on an idle data connection.
    TLSRenegotiate              required off
</IfModule>