1. A network is ...
   1. Any large computer.
   2. Two or more computers connected together.
   3. Three or more computers connected together.
   4. At least two LANs connected together.
   (See Section 1.1, Your Vulnerable Computer System.)
   
2. When you hear about an incident of computer crime ...
   1. You are getting an accurate representation of the incidence of computer crime globally.
   2. It is probably exaggerated.
   3. You are only hearing about a very small percentage of the actual incidence of computer crime globally.
   4. None of the above.
   (See Section 1.2, A Startling Discovery by the Department of Defense.)
   
3. LAN stands for ...
   1. Local Area Network.
   2. Large Area Network.
   3. Large Area Node.
   4. Locally Aired Network.
   (See Section 1.3, The Truth About Networks and the Internet.)
   
4. When two or more LANs are connected together, they form a/an ...
   1. World Area Network.
   2. Wide Area Network.
   3. Secure ID address.
   4. IP address.
   (See Section 1.3, The Truth About Networks and the Internet.)
   
5. What is the unit of information that is used to transfer other information from one computer system to another?
   1. The Internet.
   2. The LAN.
   3. The packet.
   4. The computer.
   (See Section 1.3, The Truth About Networks and the Internet.)
   
6. The sending and receiving of packets on a LAN is similar to ...
   1. The sending and receiving of radio transmissions.
   2. Two people talking on the telephone.
   3. Three or more people talking on the telephone via a "conference call".
   4. A traffic accident.
   (See Section 1.3, The Truth About Networks and the Internet.)
   
7. Promiscuity mode ...
   1. Is the same as an IP address.
   2. Enables your computer to receive anything that is sent across your network.
   3. Gives your computer more memory.
   4. Enables your computer to operate faster.
   (See Section 1.3, The Truth About Networks and the Internet.)
   
8. An IP address ...
   1. Is the same as an email address.
   2. Uniquely identifies the computer you are on.
   3. Both a and b.
   4. None of the above.
   (See Section 1.4, The Frightening Reality of Computer Crime.)
   
9. A firewall sits ...
   1. At the junction of the Internet and the LAN.
   2. Directly on the LAN.
   3. On your IP address.
   4. Directly on the Internet.
   (See Section 1.5, The Firewall.)
   
10. What does a firewall look for before it decides whether or not to let you past?
    1. Your email address.
    2. Your IP address.
    3. Promiscuity mode.
    4. None of the above.
    (See Section 1.5, The Firewall.)
    
11. To get past a firewall, a cracker might program his computer to look like it has your IP address. This is called ...
    1. Sequence number prediction.
    2. Bandwidth modification.
    3. LAN incognito.
    4. IP spoofing.
    (See Section 1.5, The Firewall.)
    
12. In order to use a stolen Secure ID Card, the cracker still needs to know your ...
    1. LAN identification code.
    2. Email address.
    3. Password.
    4. Sequence number.
    (See Section 1.6, Hardware Tokens---The Secure ID Card.)
    
13. Why is hijacking more commonplace now than it was ten years ago?
    1. Computers are less expensive.now.
    2. Computers are more powerful now.
    3. Both a and b above.
    4. None of the above.
    (See Section 1.7, Hijacking.)
    
14. What do two computers use to communicate the "validity" of each other's packets?
    1. Sequence numbers.
    2. IP challenge.
    3. Hijacking.
    4. IP spoofing.
    (See Section 1.7, Hijacking.)
    
15. The inclusion of Secure ID Cards and firewalls practically guarantees that your network will be secure against attacks by crackers.
    1. True.
    2. False.
    (See Section 1.7, Hijacking.)
    
16. Surveillance is just as important as, if not more important than, a firewall in a complete network security package.
    1. True.
    2. False.
    (See Section 1.10, Surveillance: Your Own Secret Agent.)

2.1 Summary and Vocabulary Builder

Jennifer's IP address is a number that uniquely identifies her computer.

Jennifer's computer is connected to other computers on a Local Area Network (LAN).

Jennifer's LAN is connected to other LANs, forming a Wide Area Network (WAN).

Jennifer's WAN is connected to other WANs all across the world, forming the Internet.

The information Jennifer sends out on the Internet is broken down into packets.

Each packet has a sequence number, which ensures the validity of the packet.

A cracker is a person who makes his living breaking into computer systems.

A cracker can program his computer to promiscuity mode and receive Jennifer's packets, thereby learning her passwords and user names.

Jennifer can try to stop the cracker from getting onto her network by putting up a firewall. A firewall checks the IP address of anyone attempting to access Jennifer's network, and does not let anyone through who does not have the proper IP address.

A cracker can obtain Jennifer's IP address and program his computer to look like it has her IP address so that the firewall will let him in. This is called IP spoofing.

To foil the cracker's IP spoofing attempts, Jennifer can employ the use of a Secure ID Card. A Secure ID Card ensures that Jennifer is who she says she is by enabling her to communicate with a similar Secure ID Card on the firewall.

A cracker can get around Jennifer's Secure ID Card defense by using sequence number prediction to hijack her session.

Jennifer can protect her network against hijacking through the use of a Virtual Private Network (VPN). A VPN encrypts the data that Jennifer sends, so that the cracker cannot read it.