static int pptp_connect(void)
{
    if ((!pptp_server && !pptp_client) || (pptp_server && pptp_client))
    {
        fatal("PPTP: unknown mode (you must specify pptp_server or pptp_client option)");
        return -1;
    }

    if (pptp_server) return pptp_start_client();
    return pptp_start_server();
}