protected String checkConnected(String host) {
        if( m_connected) {
            m_anyWrapper.error(EClientErrors.NO_VALID_ID, EClientErrors.ALREADY_CONNECTED.code(),
                    EClientErrors.ALREADY_CONNECTED.msg());
            return null;
        }
        if( isNull( host) ) {
            host = "127.0.0.1";
        }
        return host;
    }