public String askIP() {
        System.out.println(ASK_IP);
        if (terminal.hasNext(IPV4_PATTERN)) {// verificamos que sea un puerto valido
            String ip = terminal.nextLine();
            if (ip.equals(SERVER))
                return SERVER_IP;
            return ip;
        } else {
            System.out.println(INVALID_IP);
            terminal.nextLine();
        }
        return askIP();
    }