How use Passive-Mode in FtpWebRequest & fix PASV error in .Net 3.5 & Define port-range by codes

please see my windows form codes first : ``` using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; namespace my_prog { public partial class Form1 : Form { public Form1() { InitializeComponent(); } string ftp_username = "goodzilla_user"; string ftp_password = "goodzilla_pass"; string ftp_remote_host = @"ftp://11.11.111.11"; private void Form1_Load(object sender, EventArgs e) { UploadFile("d:\\test.txt", ftp_remote_host + @"/test.txt", ftp_username, ftp_password); } #region UploadFile Method /// <summary> /// Methods to upload file to FTP Server /// </summary> /// <param name="_FileName">local source file name</param> /// <param name="_UploadPath">Upload FTP path including Host name</param> /// <param name="_FTPUser">FTP login username</param> /// <param name="_FTPPass">FTP login password</param> /// public void UploadFile(string _FileName, string _UploadPath, string _FTPUser, string _FTPPass) { System.IO.FileInfo _FileInfo = new System.IO.FileInfo(_FileName); // Create FtpWebRequest object from the Uri provided System.Net.FtpWebRequest _FtpWebRequest = (System.Net.FtpWebRequest)System.Net.FtpWebRequest.Create(new Uri(_UploadPath)); // Provide the WebPermission Credintials _FtpWebRequest.Credentials = new System.Net.NetworkCredential(_FTPUser, _FTPPass); // By default KeepAlive is true, where the control connection is not closed // after a command is executed. _FtpWebRequest.KeepAlive = false; // set timeout for 20 seconds _FtpWebRequest.Timeout = 20000; // Specify the command to be executed. _FtpWebRequest.Method = System.Net.WebRequestMethods.Ftp.UploadFile; // Specify the data transfer type. _FtpWebRequest.UseBinary = true; // Notify the server about the size of the uploaded file _FtpWebRequest.ContentLength = _FileInfo.Length; // The buffer size is set to 2kb int buffLength = 2048; byte[] buff = new byte[buffLength]; // Opens a file stream (System.IO.FileStream) to read the file to be uploaded System.IO.FileStream _FileStream = _FileInfo.OpenRead(); try { // Stream to which the file to be upload is written System.IO.Stream _Stream = _FtpWebRequest.GetRequestStream(); // Read from the file stream 2kb at a time int contentLen = _FileStream.Read(buff, 0, buffLength); // Till Stream content ends while (contentLen != 0) { // Write Content from the file stream to the FTP Upload Stream _Stream.Write(buff, 0, contentLen); contentLen = _FileStream.Read(buff, 0, buffLength); } // Close the file stream and the Request Stream _Stream.Close(); _Stream.Dispose(); _FileStream.Close(); _FileStream.Dispose(); MessageBox.Show("Done"); } catch (Exception ex) { MessageBox.Show(ex.Message, "Upload Error", MessageBoxButtons.OK, MessageBoxIcon.Error); } } #endregion } } ``` i am using UploadFile method for uploading my data to my windows server 2008 r2 server. these codes in .net 4 work perfect and my problem is about .net 3.5. in .net 3.5 i got this error : "The server returned an address in response to the PASV command that is different than the address to which the FTP connection was made." for below reasons i do n't want to use `active mode` : as you know passive mode is better that active mode for connectivity... when i am using active mode in .net 3.5 and turn the Proxy Software on i got the error below : "The underlying connection was closed: The server committed a protocol violation." but .net 4 has no problem with that Proxy Software and passive mode and i can not switch to .net 4 because of my users... so how can i fix passive mode error in .net 3.5? in every thread in stack people say just use : ``` _FtpWebRequest.UsePassive = false; ``` and this is not my answer! Note : firewall in both server and client is off The OTHER QUESTION IS : is it possible to define port-range of pssive mode by codes? i asked this question in this thread because i thought by doing that we can fix that PASV error and help passive-mode to do it's job faster... EDIT : i found the thread below & i think i have the situation in reply #2, ftp-problem i have two network adapters in my server and the ip of each one inside server is like 192.168.5.?? & 192.168.5.?? but my two public ip addresses are different. so how can i fix that error by changing something in my codes or in my windows server 2008-r2 VPS and why that error only appears in .net 3.5 and in .net 4 we don't have it? i have full access to my server and can change every thing that is necessary. thanks in advance