FluentFTP - 连接时出现错误“尝试从套接字流中读取数据超时！”答案

【问题标题】：FluentFTP - Getting error while connecting "Timed out trying to read data from the socket stream!"FluentFTP - 连接时出现错误“尝试从套接字流中读取数据超时！”
【发布时间】：2017-12-07 07:20:31
【问题描述】：

得到

尝试从套接字流中读取数据时超时！

使用 FluentFTP 连接到 FTP 时。

下面是我用来连接的源代码：

Console.WriteLine("Configuring FTP to Connect to {0}", hostname);
ftp = new FtpClient(hostname,port,new NetworkCredential(username,password));               
ftp.ConnectTimeout = 600000;               
ftp.ReadTimeout = 60000;
ftp.EncryptionMode = FtpEncryptionMode.Explicit;
ftp.SslProtocols = System.Security.Authentication.SslProtocols.Tls;
ftp.ValidateCertificate += new FtpSslValidation(OnValidateCertificate);
ftp.Connect();
Console.WriteLine("Connected to {0}", hostname);

ftp.SetWorkingDirectory(foldername);
Console.WriteLine("Changed directory to {0}", foldername);

void OnValidateCertificate(FtpClient control, FtpSslValidationEventArgs e)
{
    // add logic to test if certificate is valid here
    e.Accept = true;
}

用于成功连接的 FileZilla 日志文件。我可以通过 FileZilla 连接该位置。日志片段如下：

2017-12-08 13:34:33 17672 1 Status: Connecting to xx.xx.xx.xx:990...
2017-12-08 13:34:33 17672 1 Status: Connection established, initializing TLS...
2017-12-08 13:34:33 17672 1 Status: Verifying certificate...
2017-12-08 13:35:06 17672 1 Status: TLS connection established, waiting for welcome message...
2017-12-08 13:35:06 17672 1 Response: 220-Microsoft FTP Service
2017-12-08 13:35:06 17672 1 Status: Invalid character sequence received, disabling UTF-8. Select UTF-8 option in site manager to force UTF-8.
2017-12-08 13:35:06 17672 1 Response:     Warning: This IT system is restricted to company authorised users only, including authorised third parties. Unauthorised access or use is a violation of Company’s policies and potentially the law. 
2017-12-08 13:35:06 17672 1 Response:     
2017-12-08 13:35:06 17672 1 Response: 220 Our IT systems may be monitored for administrative and security reasons. By proceeding, you acknowledge that you have read and understood this notice and that you consent to the monitoring. [ftps0]
2017-12-08 13:35:06 17672 1 Command: USER ftp_usr_comp_ext
2017-12-08 13:35:06 17672 1 Response: 331 Password required
2017-12-08 13:35:06 17672 1 Command: PASS ****************
2017-12-08 13:35:06 17672 1 Response: 230 User logged in.
2017-12-08 13:35:06 17672 1 Command: SYST
2017-12-08 13:35:06 17672 1 Response: 215 Windows_NT
2017-12-08 13:35:06 17672 1 Command: FEAT
2017-12-08 13:35:06 17672 1 Response: 211-Extended features supported:
2017-12-08 13:35:06 17672 1 Response:  LANG EN*
2017-12-08 13:35:06 17672 1 Response:  UTF8
2017-12-08 13:35:06 17672 1 Response:  AUTH TLS;TLS-C;SSL;TLS-P;
2017-12-08 13:35:06 17672 1 Response:  PBSZ
2017-12-08 13:35:06 17672 1 Response:  PROT C;P;
2017-12-08 13:35:06 17672 1 Response:  CCC
2017-12-08 13:35:06 17672 1 Response:  HOST
2017-12-08 13:35:06 17672 1 Response:  SIZE
2017-12-08 13:35:06 17672 1 Response:  MDTM
2017-12-08 13:35:06 17672 1 Response:  REST STREAM
2017-12-08 13:35:06 17672 1 Response: 211 END
2017-12-08 13:35:06 17672 1 Command: PBSZ 0
2017-12-08 13:35:07 17672 1 Response: 200 PBSZ command successful.
2017-12-08 13:35:07 17672 1 Command: PROT P
2017-12-08 13:35:07 17672 1 Response: 200 PROT command successful.
2017-12-08 13:35:07 17672 1 Status: Logged in
2017-12-08 13:35:07 17672 1 Status: Retrieving directory listing of "/Prod/Outbound"...
2017-12-08 13:35:07 17672 1 Command: CWD /Prod/Outbound
2017-12-08 13:35:07 17672 1 Response: 250 CWD command successful.

堆栈跟踪：

   at FluentFTP.FtpSocketStream.Read(Byte[] buffer, Int32 offset, Int32 count)
   at FluentFTP.FtpSocketStream.ReadLine(Encoding encoding)
   at FluentFTP.FtpClient.GetReply()
   at FluentFTP.FtpClient.Handshake()
   at FluentFTP.FtpClient.Connect()
   at ASOSSFTP.DownloadFile.DownloadFileFromFTP()

【问题讨论】：

标签： c# .net ftp ftps fluentftp

【解决方案1】：

在 FileZilla 中，您正在连接到隐式 FTPS 端口 990。

如果在 C# 中也使用此端口，则不能使用 FtpEncryptionMode.Explicit。

使用FtpEncryptionMode.Implicit。

尽管你最好连接到端口 21 并继续使用FtpEncryptionMode.Explicit，如果该端口可用的话。

【讨论】：

【解决方案2】：

以下代码是获取 FluentFtp（至少 nuget (1.0.5824.34026) 使用安全连接所需的全部内容。

        FtpClient fclient = new FtpClient(hostname, username, password); // or set Host & Credentials

        fclient.EncryptionMode = FtpEncryptionMode.Implicit;  
        fclient.SslProtocols = SslProtocols.Tls12;

        //client.Port = 990;  // Not required - probably gives you exceptions if you try to set it. 

        fclient.Connect();
        fclient.UploadFile(@"C:\tmp\a.txt", "big.txt");

【讨论】：