我在 EC2 上安装了 Ubuntu 14.04，安装了 vsftpd 3.0.2
我已经设置了 SSL 证书，并且我的 vsftpd.conf 是：
listen=YES
anonymous_enable=NO
local_enable=YES
write_enable=YES
dirmessage_enable=YES
use_localtime=YES
connect_from_port_20=YES
xferlog_std_format=YES
chroot_local_user=YES
secure_chroot_dir=/var/run/vsftpd/empty
pam_service_name=vsftpd
rsa_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
rsa_private_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
ssl_tlsv1=YES
ssl_sslv2=NO
ssl_sslv3=NO
ssl_enable=YES
allow_anon_ssl=NO
force_local_data_ssl=NO
force_local_logins_ssl=NO
require_ssl_reuse=NO
debug_ssl=YES
validate_cert=NO
ssl_ciphers=HIGH
pasv_address=[***** public IP ******]
pasv_enable=YES
pasv_min_port=1024
pasv_max_port=1048
当使用‘通过 TLS 显式 FTP 的 FTP’从 FileZilla 连接时，我得到以下信息：
Status: Resolving address of tcff-ftp.zuriar.net
Status: Connecting to [********]:21...
Status: Connection established, waiting for welcome message...
Response: 220 (vsFTPd 3.0.2)
Command: AUTH TLS
Response: 234 Proceed with negotiation.
Status: Initializing TLS...
Status: Verifying certificate...
Command: USER [******]
Status: TLS/SSL connection established.
Response: 331 Please specify the password.
Command: PASS ************
Response: 230 Login successful.
Command: OPTS UTF8 ON
Response: 200 Always in UTF8 mode.
Command: PBSZ 0
Response: 200 PBSZ set to 0.
Command: PROT P
Response: 200 PROT now Private.
Status: Connected
Status: Retrieving directory listing...
Command: PWD
Response: 257 "/"
Command: TYPE I
Response: 200 Switching to Binary mode.
Command: PASV
Error: GnuTLS error -15: An unexpected TLS packet was received.
Error: Disconnected from server: ECONNABORTED - Connection aborted
Error: Failed to retrieve directory listing
这是什么错误信息？我该如何修复它？据我所知，这与切换到被动模式有关...谢谢。