c# - 服务器响应 PASV 命令返回的地址与建立 FTP 连接的地址不同

Question

System.Net.WebException: The server returned an address in response to the PASV command that is different than the address to which the FTP connection was made.
at System.Net.FtpWebRequest.CheckError()
at System.Net.FtpWebRequest.SyncRequestCallback(Object obj)
at System.Net.CommandStream.Abort(Exception e)
at System.Net.FtpWebRequest.FinishRequestStage(RequestStage stage)
at System.Net.FtpWebRequest.GetRequestStream()
at BackupDB.Program.FTPUploadFile(String serverPath, String serverFile, FileInfo LocalFile, NetworkCredential Cred) in D:\PROJEKTI\BackupDB\BackupDB\Program.cs:line 119

代码:

FTPMakeDir(new Uri(serverPath + "/"), Cred);
FtpWebRequest request = (FtpWebRequest)WebRequest.Create(serverPath+serverFile);
request.UsePassive = true;
request.Method = WebRequestMethods.Ftp.UploadFile;
request.Credentials = Cred;
byte[] buffer = new byte[10240];    // Read/write 10kb

using (FileStream sourceStream = new FileStream(
    LocalFile.ToString(), FileMode.Open))
{
    using (Stream requestStream = request.GetRequestStream())
    {
        int bytesRead;
        do
        {
            bytesRead = sourceStream.Read(buffer, 0, buffer.Length);
            requestStream.Write(buffer, 0, bytesRead);
        } while (bytesRead > 0);
    }
    response = (FtpWebResponse)request.GetResponse();
    response.Close();
}

Answer 1

我的天啊。在这里购买他们的第 3 方解决方案而不是通知您更改一行代码的所有迎合是怎么回事？

尝试切换被动值以查看哪个有效:

    request.UsePassive = false;

这可能取决于机器(客户端和服务器)之间的防火墙。

我注意到如果我通过我们的防火墙，那么我需要将它保留为 True，否则它会返回异常:

The remote server returned an error: (500) Syntax error, command unrecognized.

但是，如果我在防火墙后面(比如数据中心内的两台机器直接相互连接)，那么我需要将它设置为 False，否则它将返回异常:

The server returned an address in response to the PASV command that is different than the address to which the FTP connection was made.

如果这行得通并且你想让你的解决方案更具适应性，你可以使用默认的 True 值将你的请求包装在一个 try-catch block 中，如果你得到 500 错误，然后将 UsePassive 切换为 False 并重试.