WWW and Internet Communication

1. WWW and Internet Communication Compiled by G.F Kalumuna January 2014

2. Introduction • The Internet (Net) is a loose association of thousands of networks and millions of computers across the world that all work together to share information. It is a global system of computers that carries data and makes the exchange of information possible. • The World Wide Web is a subset of the Net. The World Wide Web enables simple and intuitive navigation of Internet sites through a graphical user interface (GUI). Computers having the proper hardware can connect to the Internet via an Internet Service Provider (ISP).

3. What is the internet? • The Internet is a worldwide system of computers joined by a common set of networking and software protocols. • Each computer in this global system of computers has its own unique address - the Internet Protocol (IP) address.

4. History The Internet (Net) launched in 1969 by Advanced Research Project Agency Network (ARPANET) • ARPANET, US computer network • Google why ARPANET was created?

5. What is the internet?... • Since 1983, the Internet has grown beyond its expectation into an increasingly commercial and popular medium. • By the mid-1990s the Internet connected millions of computers throughout the world.

6. What is the internet?... • We often hear the Internet referred to as the "information superhighway" and this analogy describes the Internet accurately. • “Think of the Internet as a huge mass transit system with a few main subway lines that intersect at certain points. Connecting to the main subway lines are commuter rails, bus lines, and ferry boats that spread out and crisscross the area” • The main lines carry the bulk of the traffic and are collectively known as the Internet backbone. • The biggest networks in the system form this backbone, which is owned by the major Internet Service Providers (ISPs).

7. Simple definition of internet • A vast network of networked computers covering the whole world • Collection of various networks around the world

8. What is the internet?...

9. WWW • Also called the web, or www • Introduced in 1992 in Switzerland by the Centre for European Nuclear Research (CERN)

10. What is the WWW? • The World Wide Web (WWW) is a subset of the Net--a collection of interlinked documents that work together using a specific Internet protocol called Hypertext Transfer Protocol (HTTP). • In other words, the Internet exists independent of the Web, but the Web can't exist without the Internet. • Web pages are written in Hypertext Markup Language (HTML), which tells the Web browser what to display.

11. What is the WWW? • The significant feature of the Web is its ability to link pages to one another. Just click a link, and you're at a Web site on the other side of the world.

12. Simple definition of WWW • A multimedia based collection of information, services, and web sites supported by the Internet Note: • Prior to the discovery of the Web, the Internet was all text

13. How do we get connected? • Nearly anyone can connect their computer to the Internet and immediately communicate with other computers on the Net. With the advent of high-speed modems for digital communication over common phone lines and now cable lines, many people and organizations take advantage of the network's advanced and global communications.

14. How do we get connected?... • To get connected you need the following Two Resources: • Connection to the Internet via a modem or network connection The most common way to get connected now a days is through your cable line, telephone line, modem etc ALL through Internet Service Providers (ISPs) 2. A web browser such as Internet Explorer

15. Web browsers • Web browsers are software applications that provide access to and allow viewing of Internet resources. • By using a web browser you can view information in either a text-only format, using a browser such as Lynx, or in a graphical text format using a browser such as Internet Explorer. • Graphics can refer to images, animations, or movies. • Other well-known web browsers include Firefox, Google Chrome, and Safari. • Web browsers are primarily used to view web pages, although most can also be used to access newsgroups and email as well.

16. Movement of Information on the Internet • Information moves from one computer to another following a communications protocol • A communications protocol is a set of rules computers follow to transfer information

17. How does the Internet work? • When you request or send information such as a webpage or email, the computer breaks the request into smaller, more manageable pieces called packets. Each of these packets contains both the sender's Internet address and the receiver's address. Every packet is sent first to a gateway computer that understands a small portion of the Internet. • This gateway computer reads the destination address and forwards the packet to an adjacent gateway, closer to the packets destination, it will in turn read the destination address and so forth across the Internet until a gateway recognizes the packet as belonging to a computer within its immediate neighborhood or domain.

18. How does the Internet work?... • Regardless of what operating system you use (Mac, PC, or Unix) to connect to the Internet, the computers all basically speak the same language, which allows you to exchange information with someone next door or across the planet. • Because a message can be divided in numerous packets, each packet may be sent by a different route across the Internet. Because the IP just delivers the packets, they can arrive in a different order than the order they were sent in. The Transmission Control Protocol (TCP) has the job of putting them back in the right order.

19. How does the Internet work?...

20. Communications Protocol • Transfer Control Protocol/Internet Protocol (TCP/IP) • Basic communications protocol for the Internet to work • Hypertext Transfer Protocol (http) • Supports the movement of info over the web • Hence, web site addresses start with http • File Transfer Protocol (FTP) • Allows the transfer of files from one computer to another

21. Online Safety • When you are connected to the internet you enter a very public place. You need to be cautious and minimize your personal risk while online. • Your computer can be exposed to various types of computer viruses, worms, phishing scams, hoaxes, adware, and spyware.

22. Why is my computer not secure? Over the Internet • Every time you connect to the Internet you enter a very public space. This means what you do online may be visible or monitored by people, such as network administrators, that may be invisible to you. • Also, unwanted program such as virus, worm, spyware etc may affect your computer or system. • Hackers (attackers), may also affect your computer or system • Therefore, it is very important to be responsible when connected to the internet and minimize your personal risk.

23. What is a virus? A computer virus is a small program written to alter the way a computer operates, without the permission or knowledge of the user. A virus must meet two criteria: • It must execute itself. It will often place its own code in the path of execution of another program. • It must replicate itself. For example, it may replace other executable files with a copy of the virus infected file. Viruses can infect desktop computers and network servers alike.

24. What is a virus?... • Some viruses are benign; however, most are malignant. • A benign viruswill do no real damage to your computer. They simply conceal themselves and display a message of some sort at some time. Some simply replicate and take up resources such as disk space or CPU time. • A malignant virus tries to inflict damage to your computer. Malignant viruses may alter one or more of your files or programs so that they do not work properly. The virus may also cause programs to terminate abnormally, cause incorrect information to be written to your documents, alter directory information, delete files, or even erase your entire hard disk.

25. What is a virus?... • Specifically, a computer virus is a threat to the security and integrity of your computer system which could cause the loss or alteration of programs and data and can spread from program to program, computer to computer, or system to system without direct human intervention or even intention.

26. What is a worm? • Worms are programs that replicate themselves from system to system without the use of a host file. This is in contrast to viruses, which requires the spreading of an infected host file. A worm only depends on active network connections.

27. What is a Trojan Horse? • Trojan Horses are impostors--files that claim to be something desirable but, in fact, are malicious. A very important distinction between Trojan horse programs and true viruses is that they do not replicate themselves. Trojans contain malicious code that when triggered cause loss, or even theft, of data. For a Trojan horse to spread, you must, invite these programs onto your computers--for example, by opening an email attachment or downloading and running a file from the Internet. The PWSteal.Trojan is a Trojan.

28. How do I protect my computer from viruses? There is no absolute protection to prevent computer viruses entirely, but protection is necessary to limit the chance of an infection. Some ways to protect your computer are: • Implement safe computing practices. • Use up-to-date antivirus software. • Have clean, up-to-date backups of all your important data. • Have a clean, and fairly new boot diskette. • Scan all removable media, downloads, and email attachments; always scan any new files before executing them. • Take removable media out of the computer when finished with them and especially before starting or restarting the computer. • Don't let your email system automatically open documents or execute file attachments. • Don't use illegal software, since they have a higher chance of being infected than legitimate commercial or shareware software. • Make sure anyone who uses your computer also follows your safe computing practices.

29. How do I protect my computer from viruses?... • The most effective way to protect your computer is to install antivirus software on to your computer. Symantec Norton Antivirus, Dr. Solomon's Anti-Virus, or McAfee Virus Scan, are just a few antivirus software applications which find virus infections and can automatically contain or delete them. You need to update your computer’s virus definitions to help protect your computer from viruses. Virus definitions are files that provide information to antivirus software to find and repair viruses. Since new viruses are created all the time it is crucial that you keep your virus definitions up-to-date. Simply installing virus protection and never updating the virus definitions will not protect your computer.

30. How do I protect my computer from viruses?... • Virus definitions must be kept up to date since viruses are constantly changing. Please update as often as possible. You must be online to complete the following steps. 1. Open your anti-virus software client from your programs menu, or by double clicking on the icon at the bottom right hand corner of your screen. • For Symantec Anti-Virus, double click on the gold shield.

31. How do I protect my computer from viruses?... 2. Check the date for the virus definitions. The date should be recent. Click on the Update button and follow the on screen instructions to complete the install. • For Symantec anti-virus, click on the Live Update button and click on Next until the update finishes. *You may have to close the window and reopen for the Version date to refresh.

32. How do I protect my computer from viruses?...

33. What is Phishing? • Phishing is an attempt to get you to reveal logins, passwords, account numbers and other personal information. Phishers send an email or pop-up message that claims to be from a business or organization that you deal with - for example, your Internet service provider (ISP), bank, credit card company, online payment service (such as PayPal), or even a government agency. The message usually says that you need to "update" or "validate" your account information. It might threaten some dire consequence if you do not respond. The message directs you to a Web site that looks just like a legitimate organization's site, but it is not. The purpose of the bogus site is to trick you into divulging your personal information so the phishers can steal your personal information.

34. How do I respond to a phishing attempt? • If you get an email or pop-up message that asks for personal or financial information, do not reply or click on the link in the message. Legitimate companies do not ask for this information via email. If you are concerned about your account, contact the organization in the email using a telephone number you know to be genuine, or open a new Internet browser session and type in the company's correct Web address. In any case, do not cut and paste the link in the message.

35. What is a Hoax? • Hoaxes usually arrive in the form of an email. Please disregard the hoax emails - they contain bogus warnings usually intent only on frightening or misleading users. The best course of action is to merely delete these hoax emails. Although it is possible to be emailed an infected executable file or document containing a macro virus, by simply reading your email, you will not get a computer virus. You would have to open the file attachment to actually get a virus. Therefore, precautions should be taken when dealing with such attachments.

36. What are Adware and Spyware? • Adware is unwanted advertising banners, pop-ups, pop-unders, etc. in your web browser. Spyware is a catchall term for several types of malicious software. The consequences of a moderate to severe spyware infection (privacy issues aside) generally include a substantial loss of system performance and major stability issues (crashes and hangs). Spyware consists of computer software that gathers information about a computer user without the user’s knowledge or informed consent, and then transmits this information to an external entity.

37. What are Adware and Spyware?... How does it get onto your computer? • It often arrives attached to other software that you intentionally install. Many ‘freeware’ and ‘Shareware’ programs that you download over the net include from one to several parasite programs that will silently install themselves as you install the software that you actually wanted. Some may also arrive through email. Unlike viruses, these usually announce themselves. Many install themselves on your system when you simply visit a web site that hosts them. These are know as ‘Drive-by Installations’.

38. Surfing the WWW Introduction • With the knowledge you now have about the Internet and the WWW, you can utilize this knowledge to find valuable and not so valuable information on the web. The fastest way to find information is to use a search engine. In this lesson, we will discuss navigating the WWW, using search engines, downloading plug-ins, and most importantly protecting your computer from viruses.

39. How do I navigate the WWW? • Every computer connected to the Internet has its own unique address: a number whose format is defined by the Internet Protocol (IP), which is the standard that defines how messages are passed from one machine to another and how each connected computer is addressed on the Internet. Each item on a computer such as a web page has its own unique address as well, called the Uniform Resource Locator (URL). Think of it as a web address. Every web page on the Internet has a unique URL address that identifies the location of that page on a server. For example, a web page address may look like the following:

40. How do I navigate the WWW?...

41. How do I navigate the WWW?... • HTTP: The first part of the address (http) is the protocol. The protocol identifies a manner for interpreting transmitted computer information. Internet web pages use http (Hypertext Transfer Protocol). Web pages can be exchanged over the Internet because web browsers (which read the pages) and Web servers (which store and serve the pages) both understand HTTP.

42. How do I navigate the WWW?... There are also other various types of protocols you need to be familiar with. These are: • ftp (File Transfer Protocol) - used to transfer files to another computer via the Internet. • news - used by Usenet newsgroups. • telnet - used to login to other computers. • mailto - used to send email.

43. How do I navigate the WWW?... • WWW is the hostname. The hostname combined with the domain name specifies the computer your are connected to. Another example of a host name would be "library" in the following URL address: http://library.stedwards.edu/ • stedwards.edu is the domain name. Understanding the parts of the domain name is helpful in deciphering what type of web page you will be viewing. The domain in this example is stedwards.edu.This can be broken down into smaller parts: • stedwards- is the second-level domain. • edu - is the top level domain.

44. How do I navigate the WWW?... • stedwards- is the second-level domain. • edu - is the top level domain. The last part of the URL is the pathname. The pathname identifies the location of the web page on the server. This usually consists of one or more folder names followed by a file name with a file extension, such as html. In the existing example, the following is the pathname where the web page is located:it_dept/competency/index.html

45. How do I navigate the WWW?... • An URL is case sensitive, except for the host and domain name. This means that the pathname and filename of the URL address have to be typed in exactly the way it is shown. When a URL is spoken, unless the person specifies, then it is usually all in lower case.

46. Using Hyperlinks • The simplest way to navigate the web is to click on links, technically known as hyperlinks. Links are the connectors which one document automatically references other documents, located anywhere around the world. They are usually text or images that have a specific URL address associated with them, which makes them a connector to another web page. For example, on the St. Edward's home page, it has links to the Library, Site Index, and the Welcome statement. We can tell they are links because when you move your mouse pointer over the words, it is transformed from an arrow to a "pointing hand.“ • Once you click on one of these links, say the Library link, the SEU library web page will appear on your screen. 

47. Search Engines • Search engines can be very powerful tools when gathering information for research projects, listings for local movies, or businesses. • Many of you have probably already used a search engine, whether you realize it or not. • You may use search engine to find information for research projects, reports, dissertation, thesis etc.

48. Search Engines... • Below is a table that consists of many helpful sites that contain search engines. You can use many of these search engines to help you in your everyday life.

49. Search Engines...

50. Search Tips and techniques • Use only lower case letters to enter your search criteria. • Use quotation marks to search for an exact phrase. For example, to search for articles on Edgar Allen Poe, enter "Edgar Allen Poe" into the text box. If you entered just his full name without the quotation marks, you will find every page with Edgar or Allen or Poe in the title. That will be a much larger group of entries to sift through to the find information you need. • Be as descriptive as possible. For example, try using “19th century tables” instead of old furniture. • Including and excluding words. Use a plus (+) sign in front of a word to require that the word appear in the results. Use a minus (-) sign in front of a word to exclude it from the results. For example, you want to search on all trucks except Ford, try: trucks –Ford • Use of the words Either/Or should be in all caps. For example, search for: Colorado skiing OR snowboarding • Use of AND, OR & ANDNOT (all in capital letters)