Class+Notes+2

Networking 1. The Internet is a network of networks that uses two protocols, collectively known as TCP/IP, to control the exchange of data. 2. The first part of an email address (before the @ sign) identifies a particular computer user. The second part of an email address (after the @ sign) contains a domain name. 3. Unless the email message is short, the mail server divides the message into packets. The message is sent from mail server through zero or more intermediate routers to the mail server of the person to whom you are sending the email. The destination email server reassembles the message from the packets (if necessary) and transmits the message to the intended recipient. 4. In order to be delivered, both email and physical mail must have a valid destination address. People assume that letters sent by physical mail are private; many people assume that email should also be kept private. 5. Spam is unsolicited, bulk email. 6. A spam blocker attempts to keep spam from reaching someone’s mailbox by identifying and discarding (or routing to a special folder) emails that appear to be spam. 7. TrendMicro maintains a list of networks that either forward spam or allow spam to be created. The list is called the Realtime Blackhole List. Some Internet service providers refuse to accept email sent from hosts on the Realtime Blackhole List. 8. Email is less interactive. With email, the sender composes and mails a message. After the message is delivered, the recipient reads themessage andmay compose a reply. Because there is higher overheadwith email, messages tend to be longer and are sent less frequently. Instant messaging is more interactive. A screen displays a conversation as it unfolds. A message is sent every time one of the parties hits the “Enter” key. Because there is little overhead with instant messaging, messages are much shorter and are sent more frequently. 9. A PC bang is a Korean cybercafe in which people play persistent, on-line games. 10. A URL is a Uniform Resource Locator. Every Web page has a unique URL, enabling hyperlinks to be set up between arbitrary pages.

11. Here are five among a multitude of other uses of the Web: (a) We sell stuff in on-line auctions (such as eBay). (b) We seek medical information from on-line special interest groups of people suffering from particular diseases. (c) We learn about the weather. (d) We find out about current traffic conditions before deciding whether to leave work. (e) We get directions before driving to a place we’ve never been before. 12. There are three forms of direct censorship: government monopolization, pre-publication review and licensing and registration. Government monopolization means the government owns all the media outlets. Pre-publication review means the government must approve information before it is disseminated. Licensing and registration means a news organization must get a license from the government before operating. It is used for media with limited bandwidth, such as radio and television. 13. Broadcasters have the most limited First Amendment rights because they have a pervasive presence. Broadcasters beam signals into the privacy of the home. Since people can turn radios and televisions on and off, they may turn a device on in the middle of a show. That means that warnings at the start of a show are less effective than a warning at the front of a newspaper or magazine article. Also, broadcasting is accessible to children, even those too young to read. Restricting the access of children to radio or television is more difficult than restricting access to adult magazines or books. 14. Censorship is difficult on the Internet because: (a) The Internet supports many-to-many communication. The Internet has far more information outlets than television or radio. (b) The Internet is dynamic. Millions of computers are being added to the Internet every year. (c) The Web is huge, containing billions of pages. Nobody can keep track of everything published on the Web. (d) The Internet is global. Laws passed in one nation may have no effect outside that nation’s borders. (e) It is hard to distinguish between children and adults on the Internet. 15. The term “Internet addiction” stretches the traditional concept of addiction because the traditional definition of addiction focuses on the misuse of a chemical substance or drug. 16. The Enlightenment view of addiction is that people are responsible for the decisions they make about what they put into their bodies. Therefore, the responsibility for a person becoming addicted rests with the addict himself/herself.