收到 421 错误

Question

我正在尝试从 public ftp 服务器下载文件。这是我的 C# 源代码：

        FtpWebRequest request = FtpWebRequest.Create(new Uri("ftp://ftp.exotic-guild.de/test.exe")) as FtpWebRequest;


        request.Credentials = new NetworkCredential("anonymous@exotic-guild.de", "");
        request.UsePassive = true;
        request.UseBinary = true;
        request.KeepAlive = true;
        request.Method = WebRequestMethods.Ftp.DownloadFile;
        FtpWebResponse response = request.GetResponse() as FtpWebResponse;
        System.IO.Stream responseStream = response.GetResponseStream();

        responseStream.Close();
        response.Close(); //Closes the connection to the server

这是 public_ftp 服务器的文档链接：wolkenbauer anonymus ftp documentation。

Answer 1

使用 ftp.exe ftp.exotic-guild.de 响应是：

421 Sorry, cleartext sessions and weak ciphers are not accepted on this server. Please reconnect using SSL/TLS security mechanisms. Connection closed by remote host.

所以添加：

request.EnableSsl = true;
System.Net.ServicePointManager.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors) => true;

第二行绕过证书验证，因为所提供的证书由于某种原因无效（您可能想调查一下）。

The remote certificate is invalid according to the validation procedure

收到 421 错误

Getting a 421 error

c#

ftp

ftp-client