async def find_free_port(start_port=49152, end_port=65535, max_attempts=100):
    """Find a free port in the ephemeral port range."""
    for _ in range(max_attempts):
        port = random.randint(start_port, end_port)
        try:
            with closing(socket.socket(socket.AF_INET, socket.SOCK_DGRAM)) as sock:
                sock.bind(('', port))
                return port
        except OSError:
            continue
    raise RuntimeError(f"Unable to find a free port after {max_attempts} attempts")