问题
I am using FTP over implicit SSL to upload some files. I encountered the following error message
[Command] PWD
[Response] 257 "/" is current directory.
[Command] PWD
[Response] 257 "/" is current directory.
[Command] TYPE A
[Response] 200 Type set to A
[Command] PWD
[Response] 257 "/" is current directory.
[Command] PASV
[Response] 227 Entering Passive Mode (10,0,0,19,195,113)
[Command] LIST -aL
[Response] 521 PROT P required
[Command] PWD
[Response] 257 "/" is current directory.
[Command] PASV
[Response] 227 Entering Passive Mode (10,0,0,19,195,114)
[Command] LIST -aL
[Response] 521 PROT P required
[Status] Failed::FTP protocol error. 521 PROT P required.
May I know what is this error message "521 PROT P required" saying?
Thanks
回答1:
Before starting a data transfer (e.g. creating a new data connection outside the control connection to transfer files or listing) you have to specify the protection level using the PROT command. The main protection levels are P for protected (e.g. SSL encryption) or C for clear (no encryption). The server complains, because you don't specify a protection level and so it does not know how you want to get your data.
The PROT command must be implemented and used by all ftps clients.
回答2:
type the following: set ftp:ssl-protect-data true
来源：https://stackoverflow.com/questions/22615019/ftps-implicit-tls-ssl-error