def get_machines_by_vnet_interface_name(config, ifname):
    """
    Returns a list of machine that use a particular VNet interface
    :param dict config: The config generated by get_config()
    :param str ifname: The interface to check for
    :return: list of VNet machines using that interface
    """
    machines = []
    for m_name, m_data in config["machines"].items():
        for int_data in m_data["interfaces"].values():
            if int(int_data["bridge"]) == int(ifname[-1]):
                machines.append(m_name)
    return machines