code: protected HostPort get127Reply()
          throws ServerException, IOException, FTPReplyParseException
      {
          Reply reply = controlChannel.read();
  
          if (Reply.isTransientNegativeCompletion(reply)
              || Reply.isPermanentNegativeCompletion(reply)) {
              throw ServerException.embedUnexpectedReplyCodeException(
                      new UnexpectedReplyCodeException(reply), reply.getMessage());
          }
  
          if (reply.getCode() != 127) {
              throw new ServerException(ServerException.WRONG_PROTOCOL,
                                        reply.getMessage());
          }
  
          Matcher matcher = portPattern.matcher(reply.getMessage());
          if (!matcher.find()) {
              throw new ServerException(ServerException.WRONG_PROTOCOL,
                                        "Cannot parse 127 reply: "
                                        + reply.getMessage());
          }
  
          return new HostPort(matcher.group());
      }
docs: Reads a GFD.47 compliant 127 reply and extracts the port
  information from it.