我已将 proftpd 设置为使用 ssl/tls。尝试连接时收到“非法端口命令”
Finding Host xxx.nl ...
Connecting to xxx.xxx.xxx.xxx:21
Connected to xxx.xxx.xxx.xxx:21 in 0.018001 seconds, Waiting for Server
Response
Initializing SSL Session ...
220 FTP Server ready.
AUTH TLS
234 AUTH TLS successful
SSL session NOT set for reuse
SSL Session Started.
Host type (1): AUTO
USER xxx
331 Password required for xxx
PASS (hidden)
230 User xxx logged in
SYST
215 UNIX Type: L8
Host type (2): Unix (Standard)
PBSZ 0
200 PBSZ 0 successful
PROT P …