def is_existing_db_server(db_server_config):
    """
    Check if an external DB server config template is referring to an existing external DB server.
    If a DB server config template has host and port defined, it is referring to an existing server.
    :param db_server_config: External DB server config template
    :return: True if the External DB server config template is referring to an existing DB server
    """
    return db_server_config.get('host') and db_server_config.get('port')