code: public void setDataChannelAuthentication(DataChannelAuthentication type)
          throws IOException,
                 ServerException {
  
          Command cmd = new Command("DCAU", type.toFtpCmdArgument());
          try{
  
              controlChannel.execute(cmd);
  
          } catch (UnexpectedReplyCodeException urce) {
              if(!type.toFtpCmdArgument().equals("N"))
              {
                  throw ServerException.embedUnexpectedReplyCodeException(urce);
              }
          } catch(FTPReplyParseException rpe) {
              throw ServerException.embedFTPReplyParseException(rpe);
          }
  
          this.gSession.dataChannelAuthentication = type;
  
          gLocalServer.setDataChannelAuthentication(type);
      }
docs: Sets data channel authentication mode (DCAU)
  
  @param type for 2-party transfer must be
  DataChannelAuthentication.SELF or DataChannelAuthentication.NONE