问题 单项选择题

攻击者向某个设备发送数据包,并将数据包的源IP地址和目的IP地址都设置成攻击目标的地址。这种攻击被称为()。

A.SYN Flooding攻击

B.DDoS攻击

C.Ping of Death攻击

D.Land攻击

答案

参考答案:D

解析:

[考点透解] Land攻击的基本思路是:向某个设备发送数据包,并将数据包的源IP地址、源端口号与目的IP地址、目的端口号设置成相同,使某些TCP/UDP连接进入循环,从而导致被攻击主机无法提供正常的服务。 SYN Flooding攻击是指攻击者主机使用无效的IP地址,利用TCP连接的3次握手过程,使得受害主机处于开放会话的请求之中,直到连接超时。在此期间,受害主机将会连续接收这种会话请求,最终因资源耗尽而停止响应。 分布式拒绝服务(DDoS)攻击是指攻击者攻破了多个系统,并利用这些系统发送大量合法的请求来消耗和占用过多的服务资源,使得网络服务不能响应正常的请求。 Ping of Death攻击是通过构造出重组缓冲区大小的异常ICMP包进行攻击的。

阅读理解

阅读短文,选择正确答案。

    Happiness is for everyone. You don' t need to care about those people who have beautiful houses with large

gardens and swimming pools or those who have nice cars and a lot of money and so on. Why? Because those

who have big houses may often feel lonely and those who have cars may want to walk on the country roads at

their free time.

    In fact, happiness is always around you if you put your heart into it. When you are in trouble at school, your

friends will help you; when you study hard at your lessons, your parents are always taking good care of your life

and your health; when you get success, your friends will say congratulations to you; when you do something

wrong, people around you will help you to correct it. And when you do something good to others, you will feel

happy, too. All these are your happiness. If you notice a bit of them, you can see that happiness is always around

you.

    Happiness is not the same as money. It is a feeling of your heart. When you are poor, you can also say you

are very happy, because you have something else that can' t be bought with money. When you meet with

difficulties, you can say loudly you are very happy, because you have more chances to challenge yourself. So

you cannot always say you are poor and you have bad luck. As the saying goes, life is like a revolving (旋转的)

door. When it closes, it also opens. If you take every chance you get, you can be a happy and lucky person.

1. Those who have big houses may often feel _______. [ ]

A. happy

B. lonely

C. free

D. excited

2. When you fall down in a PE class, both your teacher and your classmates will ______. [ ]

A. laugh at you

B. play jokes on you

C. quarrel with you

D. help you up

3. What will your friends say to you when you make great progress? [ ]

A. Oh, so do I.

B. Congratulations.

C. Good luck.

D. It's just so so.

4. Which idea is NOT RIGHT according to the passage? [ ]

A. People who have cars would never like to walk in the open air.

B. You can get help from others when you make mistakes.

C. You can still be a happy person even if you have little money.

D. Happiness is always around you though difficulties come towards you.

5. Which of the following is this passage about? [ ]

A. Bad luck.

B. Good luck.

C. Happiness.

D. Life.

单项选择题