public class FTPClient
    {
        Socket _ftpSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        string _ftpHost = "";
        int    _ftpPort = 21;           // Default FTP port
        IPHostEntry _ftpHostEntry;

        byte[] inBuf = new byte[32 * 1024];
        int    inLen;

        public string Connect(string host, int port)
        {
            // Setting host/port
            _ftpHost = host;
            _ftpPort = port;
            _ftpHostEntry = Dns.GetHostEntry(_ftpHost);

            // Connecting to FTP Server
            _ftpSocket.Connect(new IPEndPoint(_ftpHostEntry.AddressList[0], _ftpPort));

            inLen = _ftpSocket.Receive(inBuf);
            return Encoding.ASCII.GetString(inBuf, 0, inLen); // Return CONNECT string
        }

        public string Login(string user, string password)
        {
            string retString = "";

            // Logon user to server
            _ftpSocket.Send(Encoding.ASCII.GetBytes("USER " + user + "\r\n"));
            retString = "Client: USER + " + user + "\r\n";

            inLen = _ftpSocket.Receive(inBuf);
            retString += "Server: " + Encoding.ASCII.GetString(inBuf, 0, inLen);

            _ftpSocket.Send(Encoding.ASCII.GetBytes("PASS " + password + "\r\n"));
            retString += "Client: PASS + " + password + "\r\n";

            inLen = _ftpSocket.Receive(inBuf);
            retString += "Server: " + Encoding.ASCII.GetString(inBuf, 0, inLen);

            return retString;
        }
    }