FileZilla 是非常好用的一款FTP SFTP 管理工具。 但是filezilla会报错“the server's certificate is unknown”
并且会在window中看到以下代码：
Status: Connecting to (IP Address)... Status: Connection established, waiting for welcome message... Status: Initializing TLS... Status: Verifying certificate... Status: TLS connection established. Status: Connected Status: Retrieving directory listing... Command: PWD Response: 257 "/" is current directory. Command: TYPE I Response: 200 Type set to I. Command: PASV Response: 227 Entering Passive Mode (IP, etc). Command: LIST Response: 534 Protection level negotiation failed. Error: Failed to retrieve directory listing Error: Connection closed by server
这是因为Filezilla client (3.10.0.1) 之后默认使用了“Use explicit FTP over TLS if available”
你需要在File -> Site Manager中的encryption 切换“only use plaint FTP (Insecure)”
来源：https://www.cnblogs.com/TheMiao/p/12245864.html