启用ftps
https://help.thorntech.com/docs/sftp-gateway-classic/enabling-ftps-using-vsftp/
问题一：登录后列目录后 FTP 响应500错误，提示地址正在使用
500 Illegal PORT command.
ftp: bind: Address already in use
有人说是 造成这个原因主要是由于iptables防火墙不支持
ip_nat_ftp
ip_conntrack_ftp
在linux的ftp服务器上执行下列命令即可解决
modprobe ip_nat_ftp
modprobe ip_conntrack_ftp
如此一番操作，有时确实解决了问题，
如果还不行，可以使用ftp -p 命令，尝试被动模式连接。
问题二：filezilla返回 服务器回应不可路由的地址。使用服务器地址代替。
被动模式填服务器公网地址，我填了ipv4的地址，但我发现用ipv6连接时还是会返回这个错误。但filezilla会自动改成服务器地址去连接，这样也能继续。
贴一个国外老兄的配置
# FTPS Shim TLS configuration /etc/vsftpd.conf
# Run standalone? vsftpd can run either from an inetd or as a standalone
# daemon started from an initscript.
# This directive enables listening on IPv6 sockets. By default, listening
# on the IPv6 "any" address (::) will accept connections from both IPv6
# and IPv4 clients. It is not necessary to listen on *both* IPv4 and IPv6
# sockets. If you want that (perhaps because you want to listen on specific
# addresses) then you must run two copies of vsftpd with two configuration
# files.
listen=YES
# Make sure PORT transfer connections originate from port 20 (ftp-data).
connect_from_port_20=NO
listen_port=38250
ftp_data_port=38255
# Allow anonymous FTP? (Disabled by default).
anonymous_enable=NO
# Uncomment this to allow local users to log in.
local_enable=YES
# Default umask for local users is 077. You may wish to change this to 022,
# if your users expect that (022 is used by most other ftpd's)
local_umask=022
# Activate directory messages - messages given to remote users when they
# go into a certain directory.
dirmessage_enable=YES
# If enabled, vsftpd will display directory listings with the time
# in your local time zone. The default is to display GMT. The
# times returned by the MDTM FTP command are also affected by this
# option.
use_localtime=YES
# Activate logging of uploads/downloads.
xferlog_enable=YES
# If you want, you can have your log file in standard ftpd xferlog format.
# Note that the default log file location is /var/log/xferlog in this case.
xferlog_std_format=NO
# You may override where the log file goes if you like. The default is shown below.
xferlog_file=/var/log/vsftpd.log
log_ftp_protocol=YES
debug_ssl=YES
# You may change the default value for timing out an idle session.
idle_session_timeout=600
# You may change the default value for timing out a data connection.
data_connection_timeout=120
# You may fully customise the login banner string:
ftpd_banner=Welcome to Read-Only FTPS Shim service.
# You may restrict local users to their home directories. See the FAQ for
# the possible risks in this before using chroot_local_user or
# chroot_list_enable below.
chroot_local_user=YES
allow_writeable_chroot=YES
# This option should be the name of a directory which is empty. Also, the
# directory should not be writable by the ftp user. This directory is used
# as a secure chroot() jail at times vsftpd does not require filesystem
# access.
secure_chroot_dir=/var/run/vsftpd/empty
# This string is the name of the PAM service vsftpd will use.
pam_service_name=ftp
# FTPS Passive Mode. -Define port range for passive mode connections
pasv_enable=Yes
pasv_min_port=10100