c#使用FTP协议将文件上传至unix主机

该程序原本是从windows主机A得到指定excel文档, 处理后发送邮件并上传至另一台Windows主机B, 现在主机B要变成Unix主机,并使用FTP协议, 
我在程序里找到如下上传方法,应该是Windows主机的吧..., 请问大神如果变成上传至Unix主机要怎么写呢?谢谢各位大神!! public string Upload(string FTPSubPath, string filename)
        {
            FileInfo fileInf = new FileInfo(filename);
            string uri = "ftp://" + ftpServerIP + "/" + FTPSubPath + "/" + fileInf.Name;
            FtpWebRequest reqFTP;
            // Create FtpWebRequest object from the Uri provided 
            reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(uri));
            try
            {
                // Provide the WebPermission Credintials 
                reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
                reqFTP.Proxy = null; //当你的机子使用的是代理上网时，最好加上这一行，要不然报“使用 HTTP 代理时不支持请求的 FTP 命令。”错误
             
                // By default KeepAlive is true, where the control connection is not closed 
                // after a command is executed. 
                reqFTP.KeepAlive = false;                // Specify the command to be executed. 
                reqFTP.Method = WebRequestMethods.Ftp.UploadFile;                // Specify the data transfer type. 
                reqFTP.UseBinary = true;                // Notify the server about the size of the uploaded file 
                reqFTP.ContentLength = fileInf.Length;                // The buffer size is set to 2kb 
                int buffLength = 2048;
                byte[] buff = new byte[buffLength];
                int contentLen;                // Opens a file stream (System.IO.FileStream) to read the file to be uploaded 
                //FileStream fs = fileInf.OpenRead(); 
                FileStream fs = fileInf.Open(FileMode.Open, FileAccess.Read, FileShare.ReadWrite);                // Stream to which the file to be upload is written 
                Stream strm = reqFTP.GetRequestStream();                // Read from the file stream 2kb at a time 
                contentLen = fs.Read(buff, 0, buffLength);                // Till Stream content ends 
                while (contentLen != 0)
                {
                    // Write Content from the file stream to the FTP Upload Stream 
                    strm.Write(buff, 0, contentLen);
                    contentLen = fs.Read(buff, 0, buffLength);
                }                // Close the file stream and the Request Stream 
                strm.Close();
                fs.Close();
                return "ok";
            }
            catch (Exception ex)
            {
                reqFTP.Abort();
                //  Logging.WriteError(ex.Message + ex.StackTrace);
                return ex.ToString() ;
            }
            
        }
~~~~~~~~~~~调用上面Upload方法的地方~~~~~~~~~~~~~~~~`   if (attachFiles.Length > 0)
                {
                    foreach (FileInfo attachName in oldFiles)
                    {
                        string rslt=ftpHelp_SPIL.Upload("/Jessie Test", attachName.Name);
                        if (rslt != "ok")
                        {
                            MailAbout.sendMail(strFrom, "SPILSZ", ini.Err_To, ini.Err_To, "FTP上传失败", ini.ErrSubject, sLocalOutputFilePath); ;
                        }
                    }
                }