Lesson 3Internet Applications

OverviewThe Internet is a vast, worldwide resource of information. However, because of

its size, you may wonder “How do I find the things I am interested in?” There are

basically three ways to find information on the Internet: browsing or surfing, using

directories, and using search engines. Many portal sites combine directories and

search engines to make searching for information more convenient.

This unit introduces Web clients and explains how to use them. It also looks at

the differences between each of the search methods and how to use them

effectively to research topics of professional or personal interest. The unit also

teaches you on how to locate people, lists and newsgroups. Various data transfer

methods is introduced through this unit. Adding to this, introduction on telnet and

electronic mail is provided in this unit.

Lessons

1. Web Clients

2. Introduction to Web Browsing

3. Searching the Web

4. File Transfer Protocol

5. Telnet

6. Electronic Mail

7. Uses of the Internet

Lesson 1 – Web Clients

Objectives:At the end of this lesson you will be able to:

Describe the relationship between HTTP and Web browsers

List the basics of Web browsers and Web servers

A Web browser is a TCP/IP client application that allows a user to retrieve

hypertext documents from a remote host computer called a Hypertext Transfer

Protocol (HTTP) server. HTTP is the Application Layer protocol used to request

and transmits documents on a Transmission Control Protocol/Internet Protocol

(TCP/IP) Internetwork.

Figure 3-1: Client/Server Structure of the World Wide Web

We can customize Web browsers to display pages the way we want to see them.

Web developers try to create pages that will display well in at least the two major

browsers: Microsoft Internet Explorer and Netscape Navigator. Browser users

can override the Web developer’s design by setting browsers to display specific

fonts and colors. Some users customize their settings to accommodate

Web Server Computers

Sun OS PCs and minicomputers

Windows PCs Linux/UNIX PCs and

minicomputers

IBM and other mainframe computers

Macintosh PCs

Client computers running Web browser software

Internet

DOS PCs Windows PCs

IBM and other mainframe computers

Linux/UNIX PCs and

minicomputers

Macintosh PCs

disabilities like impaired vision or color blindness, while others simply prefer to

view only certain fonts or colors. You can even “turn off” viewing images if all you

are looking for is text information and want to speed download times.

HTTP Communications

Web browsers are the front-end client software used to access HTTP servers by

means of the Internet. HTTP servers are commonly referred to as Web servers.

A typical Web server can handle thousands of client requests in a short period of

time. In a typical session, the following actions take place:

1. The Web browser sends a connection request to the HTTP server.

2. The HTTP server accepts the request and notifies the browser of the

successful connection.

3. The browser then transmits the document request to the server.

4. The server retrieves the document and transmits it to the Browser.

5. The browser receives the incoming document data and displays it for the

user.

6. After the server has transmitted the entire document, it breaks the

connection with the browser.

One reason HTTP servers can handle thousands, and perhaps millions of

requests per hour is the statelessness of the connection. Every time a client

browser wants to retrieve a document, a separate request is sent to the server. If

a user spends several hours reading a particular Web page, the server has no

knowledge of it.

The Web browser’s job is to display Hypertext Markup Language (HTML)

documents retrieved from HTTP servers. HTML is a text-based formatting

language used to generically format text. The Web browser reads the documents

and displays it as indicated by both the HTML formatting code and the user’s

display preferences stored in the browser. Because the intelligence to format and

display HTML documents is built into the browser, the documents are generally

fairly small in size.

Common TCP/IP Applications

Transmission Control Protocol/Internet Protocol (TCP/IP) software is packaged

with many applications. The predominant applications that ship with TCP/IP

software are discussed in more detail in the following sections.

Telnet

Telnet is an application that is widely used to provide remote login capability on a

TCP/IP network. Telnet is a user command and a TCP/IP protocol for accessing

remote computers. With Telnet, you can log on as a regular user with whatever

privileges you have been granted to the specific application and data on that

computer. Implementations of Telnet usually work between different operating

systems. For example, a Telnet client may be on a Window computer, and the

server may be running UNIX.

File Transfer Protocol

File Transfer Protocol (FTP), which is as old and as widely used as Telnet, uses

TCP to copy files between computers. The operation and appearance is as if we

used Telnet to connect to a remote computer. Instead of typing the usual

commands, we have to use a short list of commands to display directory listings,

etc.

Network Management

Simple Network Management Protocol (SNMP) was designed for used by central

network management stations to provide the data that a network manager needs

to detect and diagnose network problems. A central station uses SNMP to collect

data from other computers on the network. SNMP defines the format for the data,

but it is up to the central station or network manager to interpret the data.

Web Browsers

The mid-1990s market the dawn of a new era for the Internet: the beginning of

the World Wide Web. What was once the domain of command-line tools has now

become the world of the simple-to-use Web browser. Due in large part to the

graphical user interface (GUI) of modern-day computers, the ease of use and

popularity of the Internet has increased dramatically. Each time we start a

browser, it loads the HTML document specified to be our default home page. A

home page is the starting place for exploring the Internet. Home pages generally

have links to various topics of interest to the user. To get the most out of the

Internet, it is helpful to have at least a basic understanding of how to use a Web

browser. Fortunately, learning to use a browser is relatively easy, and you can do

a lot with a browser by just knowing the basics. The rest of this lesson will detail

the basics of the two major browsers and how to customize them.

The two most popular browsers are Microsoft Internet Explorer and Netscape

Navigator. Viewing Web pages in either of the two major browsers is very similar.

Some of the terminology is different and they support different plug-ins and

extended HTML capabilities.

Both the Microsoft Internet Explorer and Netscape Navigator display the Web

page in the same way, but there are differences in the tool bars. The Toolbar

Features Table lists both browsers’ tool bar buttons and their actions.

Toolbar Features

Internet

Explorer

Netscape

Navigator

Comment

Back Back Returns to the previous Web page. This button is

unavailable when you have viewed only one page.

Forward Forward Proceeds to the page you viewed before you clicked

the Back button. This button is unavailable when you

have viewed only one page or when you have not used

the Back button.

Stop Stop Stops loading the current page.

Refresh Reload Sends a new request to the server to display the page.

Home Home Displays the home page. You can designate the Web

page that you want for your home page. See

“Customizing Browsers” on page 95 for more

information.

Search Search Internet Explorer: Display the Microsoft search window

on the left side of the browser window. It allows you to

search for Web sites, people, businesses, previous

searches, or maps. Netscape: Displays Netscape’s

search page. It allows you to choose a commercial

search engine for your Web search. It contains links to

find shopping resources, news, and to search for

people and businesses.

Favorites

(Upper

tool bar)

Bookmarks

(Lower tool

bar)

Favorites and Bookmarks allow you to save the

addresses of Web sites you want to visit again. You

can create and manage folders and organize saved

addresses. In Internet Explorer, click on the Favorites

menu and select Organize Favorites. In Netscape, click

on Bookmarks and select File Bookmarks or Edit

Bookmarks.

History

(Tool bar)

Go (Menu) The History and Go functions allow you to see and click

on the Web page addresses you have recently visited.

Mail Send Page

(File

Menu)

Opens your default e-mail client to send the current

page.

Print Print Opens the Print dialog to print the current page.

Netscape Displays the MyNetscape site, which is a portal for Web

searching, news and information.

Security Displays the Netscape Security information page that

explains how Netscape’s security works and how to

change security settings.

Shop Displays the Shop@Netscape page.

Address Location Shows the current Web site address (URL). Allows you

to enter an address and press Enter to go to another

site.

Customizing Browsers

Most browsers allow you to customize the way you want text and images to

appear. You can alos set the home page, determine how many days to store the

Web sites you visit, and organize your bookmarks. This section discusses how to

customize Internet Explorer and Netscape Navigator browsers.

Internet Explorer

Internet Explorer provides an interface called Internet Options where you can

customize most of the display features and settings. Use the following list to

customize the home page, fonts and image loading, change history cache

settings, and organize favorites.

From the main menu, select Tools > Internet Options. The Internet Options

window opens. In this window you can customize way that the browser displays

Web pages. The following list describes some of the common settings you may

want to customize:

Home page

This setting determines the Web page that displays when you start an

Internet Explorer session. To change the home page to the page that is

currently displayed, click Use Current. You can also type the address of any

page and click OK.

Fonts

This feature allows you to set how text displays. In the General tab of Internet

Options window, click Fonts. You will see the Fonts Screen.

You can change the language displayed by using the Language Script drop-

down list. Change the Web page font or Plain text font in their respective lists

and click OK. To change font size, close the Internet Options window. From

the main menu select View > Text Size. Select the appropriate size, and the

new font size displays in the Web page you are viewing.

Image Loading

This setting allows you to turn off image loading while viewing Web pages.

Since many sites use images that slow download times, you may want to turn

off image loading when you are doing research or just want to speed page

loading times. To turn off image loading, from the main menu, select Tools > Internet Options. In the Internet Options window, click the Advanced tab.

Scroll down through the settings until you see the Multimedia section. Under

Multimedia, find the Show Pictures check box. The default setting is on

(checked). Click this check box to turn it off and click OK.

Temporary Internet files (browser cache)

This feature determines the amount of disk space used to save information

about the sites you have visited. In the Internet Options window, select the

General tab. In the Temporary Internet Files areas, click Settings to display

the Settings Screen.

To change the amount of disk space used to store viewed pages, move the

slider to the right or left, or enter a number in the text field and click OK.

To delete temporary files from memory, use the General tab of the Internet

Options window. In the Temporary Files area, click Delete Files to display the

Delete Files screen.

Select the Delete all offline content check box to delete files that you have

saved to view offline, or just click OK to delete temporary files.

History

This setting determines the number of days that the browser stores Web

addresses you have visited. In the Internet Options window, select the

General tab. In the History area, you can change the number of days by

using the up or down arrows or by typing another number in the text field. To

delete the stored links, click Clear History.

Favorites

This feature lets you organize your list of favorite sites. From the main menu,

select Favorites > Organize Favorites to display the Organize Favorites

Screen.

In the Organize Favorites window, click Create Folders to make a new

favorites category. To move favorites from the list, and click Move to Folder to select the location.

Cookies

This setting is a part of security options. A cookie is a small file that a Web

site places on your computer. The cookie stores information about your

preferences or about what you viewed on the site previously. The next time

you visit that site, the cookie gets sent back to the site. Cookies can also be

used to rotate the banner ads that a site sends. They can also be used to

customize pages for you based on information you have provided to the Web

site. Settings in your browser allow you to control how it handles cookies.

In the Internet Options window, click the Security tab. Click on the Internet icon. This category covers all the Web site you visit, unless you enter Web

site addresses into other categories. The default setting is Medium. This

means that the browser accepts cookies, but prompts you about security

information on Web sites. Microsoft recommends this setting, but you can

change it to High, which accepts no cookies and disables other features that

might be a security problem. For more information on security, view the

Internet Explorer Help file.

Netscape Navigator

Netscape Navigator provides an interface called Preferences, where you can

customize many display and setting options. The Preferences window allows you

to customize the home page, fonts, cache, and image loading. You can organize

your bookmarks using another menu options that we will discuss at the end of

this section. The examples in this section are taken from Netscape version 6.1.

To access Preferences, from the main menu, select Edit > Preferences. The

Preferences screen appears.

Home Page

In the Preferences window, double-click the Navigator Category. To change

the home page to the page that is currently displayed, click Use Current Page. You can also type the address of the page you want in the Home Page

location area and click OK.

History

This setting determines the number of days that the browser stores visited

Web addresses. You can change the number of days by typing another

number in the text field. To delete the stored links, Clear History.

Browser Cache

This feature determines the amount of disk space you want to use to save

information about the sites you have visited. In the Preferences window,

double-click the Advanced category. Under the Advanced options, click

Cache to display the Cache Screen.

In the Cache portion of the window, you can change the size of memory and

disk caches. You can also delete the items in the caches by clicking Clear Memory Cache or Clear Disk Cache.

Fonts

This feature allows you to set how text displays. In the Preferences window,

double-click the Appearance category. Under Appearance, click Fonts to

display the Fonts Screen.

In the Fonts portion of the window, use the pull-down menus to change the

font and size settings. The check box in this window allows you to choose to

view the fonts designated by Web pages or to always use the fonts you have

selected. Keep in mind that if you use your default fonts, Web pages may not

appear as their developers intended.

To change font size, close the Preferences window. From the main menu,

select View > Increase Font or View > Decrease Font. Keep increasing or

decreasing the font size until you reach the size you prefer. The new font size

will display in the Web page you are viewing.

Bookmarks

This feature allows you to rename, edit, or delete bookmarks. From the menu,

select Bookmarks > Manage Bookmarks. In the Bookmarks window, you

can create a new folder by selecting File > New Folder. Drag and drop a

bookmark to move it into a folder. To delete a bookmark, select the

bookmark, then select Edit > Delete.

Cookies

The Cookies setting is a part of security options. It stores information about

your preferences and can be used to customize pages for you. Settings in

your browser allow you to control how it handles cookies.

In the Preferences window, double-click the Privacy and Security Category.

Under the Privacy and Security options, click Cookies to display the Cookies

section.

In the Cookies portion of the window, you can change the security settings.

The available settings are:

Enable all cookies

This is the default setting, which is the lowest level of security. It allows

cookies from the site you are visiting, as well as foreign cookies.

Foreign cookies are cookies from other sites with a link to the site you

are visiting. For example, an advertising banner from another site

could place a cookie on your computer.

Enable cookies for the originating web site only

This setting allows cookies from the site you are visiting, but disables

foreign cookies.

Disable cookies

This setting allows no cookies.

Warn me before storing a cookie

This check box enables a prompt for each cookie. You can selectively

accept cookies when you use this feature.

Lesson 2 – Introduction to Web Browsing

Objectives:At the end of this lesson you will be able to:

Describe browsing basics

We “surf” the Internet by simply following links from one Web page to another. It

can be fun, but this random approach often does not get us the information that

we need.

Directories try to bring order to the Internet. However, the directories are limited

in scope, because the Internet is so diverse; they are limited in depth, because

the Internet is so big. Directories are still a good place to start.

Search engines find references for us by matching specific descriptions of what

we are looking for to information on the Internet. While it can be tricky to learn

how to use them well, search engines can locate obscure information that does

not appear in a directory.

Browsing Around

Casual surfing can be interesting and fun, but it is frustrating if you do not find

what you are looking for. A little common sense can go a long way in helping you

get a good start.

First, think about the topic you are interested in researching. If the topics is an

academic subject, a good place to start is the closest university. University Web

sites are great places to start if you are researching a subject covered by courses

they teach, because individual departments usually have links to more

information on each topic. Finding universities is usually simple because they all

have an .edu domain. For example, information on the University of Colorado is

at http://www.colorado.edu.

Let say your interest is less scholarly, like financial information, and then you

should check the newspaper online. The Wall Street Journal Web site at

http://www.wsj.com, has a large online presence and is a good source of

financial information. Local newspapers are also “getting on the Web” and can be

a good place to find information about local events and topics. Check for a

Uniform Resource Locator (URL) on the front page of your local paper.

Popular Web Sites

There are popular sites that contain vast deposits of information. Some a

commercial (.com) and some are government (.gov). These sites tend to cover

narrower topics, but generally do so in depth.

Cnet

The Cnet Web site at http://www.cnet.com contains information on technology-

related items including computers and the Internet. Cnet updates its home page

each day by adding new information. One good features in Cnet is that it offers

reviews and comparisons of products.

The U.S. Government

Even the U.S. government has been putting more of the large amount of

information it generates on the Web. One of the first government agencies to use

the Internet was the National Aeronautics and Space Administration (NASA).

NASA has some of the best and most enjoyable information on the Web, such as

information about space exploration, photographs from the Hubbell space

telescope, photographs of the surface of Mars and much more.

Browsing sites related to topics which you have an interest in is one of the best

ways to find information. Use bookmarks to save the sites you find while covering

the topics. Follow links from those sites to other sites, and see whether you need

to add those to your bookmarks. Soon you will have a collection of sites to help

you keep pace with the dizzying amount of information we are exposed to every

day.

Lesson 3 – Searching the Web

Objectives:At the end of this lesson you will be able to:

Describe the difference between a directory and a search engine

Describe the difference between lists, journals and conferences

Web is used to access millions of Web pages, which contain information on a

virtually unlimited number of topics. One need to learn searching methods and

tools in order to find the information needed. In this lesson you will learn the

differences between a directory and a search engine, find information about

organizations, individuals and newsgroups of interest. This lesson also covers

several means for finding information using electronic lists, electronic journals (e-

journals) and other online tools.

Portal Sites

Portal sites refer to Web sites that provide a starting place for finding information

on the Internet. These sites provide directories of sites that are organized into

categories. Search engines are also a key feature of portals, so that you can

search the Web sites that the particular search engine has indexed. The purpose

of portal sites is to provide a “one-stop shopping” area for their users. Some of

these sites encourage visitors to come back by providing personalized settings,

such as MyNetscape and MyLycos, discussed later in this lesson. Many also

provide free e-mail services, such as Yahoo! and MSN’s Hotmail.

The directories in portal sites are categorized lists of Web sites. Search engines

are Internet applications that allow you to search specific words or strings of

words to find information on the Internet.

There are many different kinds of Web sites that are portals to the Internet. Each

site tries to build user loyalty, because many of them use advertising to find the

sites. Many of the sites began as simple directories or search engines, but they

have added features over time. These features include news headlines, financial

information, maps, local events, chat rooms, and even horoscopes.

Directories

Directories organize information on the Internet into a coherent and

understandable form. Most directories are organized in a tree structure with main

topics at the top and subtopics below. As we travel down the tree, the subjects

get narrower and narrower. Sometimes it gets hard to classify sites. Take the

example “Antique Furniture Repair.” Do directories organize it under “furniture –

antiques – repair” or “furniture – repair – antiques” or “repair – furniture –

antiques?” fortunately most subdirectories have links to “related” subdirectories.

Therefore, if we are deep in the directory we can “jump across” to another branch

without going back to the top.

There are directories of many kinds. The “all of the Internet” directories try to

classify everything on the Internet. Some of the bigger ones are Yahoo!, Excite,

Lycos, and MSN (Microsoft Network). There are also directories or indexes for

specific topics. These are too numerous to mention here, but can be found using

one of the bigger directories.

Search Engines

Directories index less than 10 percent of the sites on the Internet. For finding that

“needle in haystack” on the Internet, we often need a search engine. Search

engines continually scan the Internet by indexing sites and their contents; they

then store the location information for fast retrieval.

The available search engines have different advantages and disadvantages. The

“best” one is probably the one that is easiest for you to use. Most search engines

have ways to refine a search. These include telling the search engine how to use

the keywords. Do we want to match all keywords (AND) or march any of the

keywords (OR)? Another feature is to treat a string of characters like a single

keyword. For example, “Ford Mustang” will return matches on cars, but not

Gerald Ford or Mustang horses.

Using Search Engines

These are several types of queries that search engines use. Many portal sites

provide two types of query searches: simple and advanced. There are

common command syntaxes or syntax rules for both types as follows:

For

Quotes – use quotes to have a string treated like a keyword. For

example: “sending a fax”

Capitalize – capitalize only if you want the match to be case sensitive.

For example: President Bush

Wildcards – use an asterisk (*) for wildcards. For example: fax* will

match fax, faxes, and other words starting with fax.

For simple queries, if you want all keywords to match, prefix the words with a

plus sign: +fax +paper. To exclude a word from the query, use the minus sign:

+fax –machines.

For advanced queries, use the Boolean connectors AND, OR, and NOT. AND

means both or all keywords are to be present. For example, fax AND paper, or fax AND NOT machines. OR is the default. For example: fax paper is the

same as fax OR paper. Use parentheses to make complex expressions:

(“vitamin C” OR “vitamin B12”) AND (colds OR flu OR influenza). There

are more syntax additions and variations to help you fine tune your search.

A new feature on some sites is translation, which translates foreign language

text or URLs to English, or English to a foreign language. Some sites also

allow you to choose the language of sites to search.

Popular Portal Sites

Some of the most popular portal sites are:

Yahoo!

Excite

AltaVista

Northern Light

HotBot

Google

Yahoo! (http://www.yahoo.com) – Yahoo! is one of the very first, many feel the

best, and certainly one of the biggest portal sites. If started out as a directory,

which is still its main attraction. Surprisingly, it is maintained by hand. Hundreds

of people check, classify, and review thousands of sites daily. As a result, the

links tend to be of higher quality than from a search engine and are certainly

better organized. Usually, there is also a brief review next to the site.

Yahoo! has a search engine that can search its directory (or one section of it) for

keywords. Enter a keyword (or words) in the search box and click Search. The

searcher will first try to match a topic, then sites in the topic. If it cannot match a

topic, it will try to match indexed sites and will include reviews in the results of the

keyword search. If it cannot find sites that match the keywords, Yahoo! passes

the keywords on to the Google search engine.

Yahoo! also has directories for particular countries and cities. The site includes

“Yellow Pages” and “White Pages” to help us find businesses and people.

Excite (http://www.excite.com) – Excite tends to concentrate more on the fun side

of the Internet with more entertainment-related topics. This site allows you to

search the Web, news, photos, or its directory (see the Excite Portal Screen,

below). Excite uses a unique concept-based search. The searcher is aware of

relationships between words and concepts. In addition to the results of your

query, you can use the “Zoom in” feature to get a checklist of alternative words

for your search. Also, below each link from the query is a “more like this” link.

Clicking here repeats the search, giving you links like the one you selected.

AltaVista (http://www.altavista.com) – AltaVista has been a top-rated site for

years, because it is fast and powerful. Its main power is the ability to control a

search query by adding special syntax words and control characters. This site

allows you to choose the language of the sites to search.

Northern Light (http://www.northernlight.com) – Northern Light is a search engine

with unique features. The “About” link on this page calls the site the first

“research engine”. This searcher can handle many keywords to help narrow the

search. Along with the search result, Northern Light displays Custom Search

folders down the left side of the page. These folders are unique to each search

and contain groups of like items relating to the search.

HotBot (http://www.hotbot.com) – HotBot is a popular search engine that is part

of the Lycos network, and based on the “Ink-tomi” searching technology from the

University of California at Berkeley. The unique thing about HotBot is its search

form. For both the regular search and their “Advanced Search”, checking

selections on a form refines the search query.

Google (http://www.google.com) – Google returns results quickly and ranks them

by relevance to the search. It also has an advanced search and allows you to set

preferences for you searches.

Metasearchers

Metasearchers are search engines that use a collection of search engines on the

Internet to get information. They receive results from the other engines, get rid of

duplicates, and reorganize the results. Metasearchers are useful if the search

topic is obscure, very specific or receives few hits.

Metaserach engines include:

MetaCrawler (http://www.metacrawler.com) – MetaCrawler uses results from

12 search engines, organizes the results, and delivers the links.

Dogpile (http://www.dogpile.com)

CNET’s metasearch site (http://www.search.com)

AskJeeves (http://www.ask.com)

Locating People, Lists and Newsgroups

Locating People, Companies and Organizations

In the following exercises, we use the Web to locate information about people,

companies, and organizations. The steps for locating e-mail addresses include:

1. Start your Web browser.

2. Click the Location, Web Site, Go To, or Address box in your Web browser

window. Type the URL:

http://www.infospace.com

3. when the main infospace page appears, find the White Pages section, and

click on E-mail.

The InfoSpace screen appears.

4. first, we will search for an e-mail address. This page includes a form with

several items. A good rule of thumb is to start with minimal information, so

start with just first and last names. If you get a large number of results,

then narrow the search by city, state or country.

5. now search for your own name and address.

The infospace directory includes many other search capabilities. You can find

people in white page listings, companies in yellow page listings, and search

classified advertisements.

Locating Mailing Lists

A mailing list consists of people who subscribe to an online periodical or

mailing distribution on a particular topic. A company or group can send the

same e-mail message to multiple recipients at the same time. Mailing lists are

a popular way for people to keep up with topics of interests to them. You can

find mailing lists on the sites of software companies and other vendors that

want to keep in touch with customers. You can also look for them on the sites

of professional and social organizations that use lists to post questions and

alert members of events. There are also public mailing lists that are hosted by

ISPs or other providers. Two of the most popular sites are:

ListQuest (http://www.listquest.com)

Yahoo!groups (http://www.groups.yahoo.com)

Locating Newsgroups

A newsgroup is an ongoing discussion about a subject. People post notes to

a central Internet sites and the notes are redistributed through Usenet, a

worldwide network of news discussion groups (http://www.usenet.com).

Usenet uses the Network News Transfer Protocol (NNTP). The Usenet site

requires a fee to join, but you can access newsgroups and post your own

messages from other free sites as well. Most of the sites requires you to

become a member of the site to be able to post or reply to messages.

Newsgroups are organized into subject hierarchies. The first few letters of the

newsgroup name indicate the major subject category, and subtopic names

represent sub-categories.

Getting Help on the Internet

Participating in Discussion Lists and E-Journals

Subscribing to Discussion Lists

An e-conference (also known as a listserv, discussion list, mailing list, etc.)

uses e-mail messages to create a dialog among the members of a

special-interest group. Group members address their comments to a

mailing list program hosted on a single server. The list server periodically

sends copies of the incoming messages to each member of the group. In

this way, a group member can send a message to all other members of

the group. Using e-mail is the only skill to participate in an e-conference.

Using Web-Based Help Tools

There are several methods for getting help using the Web. Web-based

encyclopedia can be used to find the meaning of terms, such as computer

and Internet terms. One popular encyclopedia is Webopedia, which

defines a wide variety of technical terms. It can be found at

http://www.webopedia.com.

Another common tool on the Web is Ask Jeeves, at (http://www.ask.com).

With this tool, you simply enter a question and it is answered for you.

Although you may not get a specific answer, you will often get enough

information to answer your question.

Lesson 4 – File Transfer Protocol

Objectives:At the end of this lesson you will be able to:

Describe the basic use of FTP

File Transfer Protocol (FTP) is a protocol designed to allow computers to

communicate with each other across the Internet to arrange for the transfer of

files from one computer to another computer.

Purpose of Browser and Server Software

Not all computers provide FTP service. Host (server) computers must run FTP

server software to manage connections from client machines requiring FTP

access to the server’s files. FTP provides clients with a “window” into the server

that displays the files that can be copied to the client machine’s storage media

(hard drive, floppy disk, Zip drive, etc.). The administrator of the FTP server

specifies which areas of the server’s hard drive are visible to the client machine,

what files can be read or written, and who can access the files. If an FTP server

and access privileges have not been set up on a host computer, then that

computer’s files cannot be accessed using FTP.

Private FTP Servers

Some FTP servers are set up for private use, and access is controlled by a user

name and password method. This means that a user must have been given

explicit access to the FTP server and assigned a unique name and password

that must be provided to the server before the user is allowed to use the server’s

facilities.

Anonymous FTP Servers

In addition to using FTP for an organization’s private internal use, there are many

public-access archives of documents and software including shareware and

public domain that can be accessed using FTP. These are accessed by what is

known as anonymous FTP where the FTP server requires a user name, but the

user name is “anonymous”. The password is normally the user’s e-mail address.

Is Anonymous FTP Really Anonymous?

When using anonymous FTP, most FTP servers will require that the user supply

his or her e-mail address as a password. This means that the archive

maintainers will have a record of the user’s e-mail address, cross-referenced with

the files the users transferred. However, most archive maintainers stipulate that

the e-mail address will be used only for their own purposes, such as

demographic studies and pursuing any abuse of the archive services. A user is

unlikely to receive unsolicited e-mail as a result of using an anonymous FTP

archive.

How Can We Use FTP?

A large number of programs can be used for FTP, with varying user interfaces.

The most basic is a program called FTP. This program offers a command line

interface, similar in some ways to a DOC or UNIX shell, which can be used to

explore the directory tree of a remote computer and transfer files. The program

has one main advantage: it is standard and has been written for most computer

platforms.

There are also numerous programs available that provide a user a more

graphical, point-and-click interface to FTP. Visit http://www.cnet.com or the

http://www.tucows.com archive for examples. Most Web browsers can also be

used to obtain files by means of FTP.

Using Command Line FTP

The following is a demonstration of a command-line FTP session, which

illustrates how some of the basic commands work:

1. If running Windows, launch the MS-DOS or Command prompt to open a

DOS window.

2. At the DOS prompt, type ftp followed by FTP site, for example:

ftp telnet.westnetinc.com

You may also type ftp at the command line. This will start the FTP program,

where you can issue further commands. To see a list of available commands,

type help at the FTP prompt. To get brief help on a particular command, type

help followed by the command name. The open command connects to the

appropriate FTP site.

Recognize that the FTP site address could just have easily been

ftp.westnetinc.com, but the same computer is being used as a Telnet server and

FTP server.

The computer responds with the following message:

1. At username: type anonymous

2. At the password: prompt, type your complete e-mail address.

3. to see what files are located in this directory, type dir and press ENTER. A

screen similar to the one in the FTP DIR Command Diagram will appear.

The first part of the file listing has a series of letters and dashes. If the first series

is a “-“,, it means the item is a file. If it is a “d”, it indicates a directory with the cd command. For example typing cd pub changes to the pub directory. You can

then type dir and the Listing of Pub Directory Diagram will appear.

Make files on the Internet are stored as binary files (as opposed to text-only

files). Binary files include executable programs Microsoft Word documents, and

Adobe Acrobat (.pdf) files. To make sure these files transfer correctly, you must

tell FTP to perform a binary file transfer. To do this, type “binary” at the FTP

prompt. This will set the rest of your FTP session to binary mode for file transfers.

This mode will work well for most file transfers. If you need to switch back to the

text-only mode, type “ASCII” at the FTP prompt.

The name of the file or directory is provided at the far right of the listing.

Glossary.doc is a file listed in this example. The size of the file is indicated by the

number to the left of the date. The file Glossary.doc is 359,912 bytes. To retrieve

the file, type the command: get Glossary.doc

The glossary.doc file will be copied to the directory you are in at the command

prompt. The command is case-sensitive, so be sure to capitalize the file name.

Type quit to close the FTP application. Type exit to close the DOS windows.

Using FTP with a Browser

You can also access an FTP site with a Web browser. First, you must be

connected to the Internet and be using a browser. After you’re connected type

the FTP site address in the space where URLs are entered. For example, to

access the Internal Revenue Service (IRS) publications FTP site, you must type

the following in your browser location area: ftp://ftp.irs.gov/pub/.

To download your file of choice, right click the file and choose to copy it to a

folder, then select the folder location.

Lesson 5 – Telnet

Objectives:At the end of this lesson you will be able to:

Describe common uses of Telnet

Telnet is another Internet Protocol that uses TCP/IP. The Telnet application

facilitates remote login; that is, users log on to a remote computer system from a

local computer. Telnet is one of the first services to take advantage of Internet

connectivity. Many years ago, before the widespread distribution of

microcomputers, terminals were used to communicate with large mainframes and

minicomputers. Telnet is simply a way to offer this same kind of interaction over a

TCP/IP network. In today’s world of fancy and flashy graphical interfaces, this

may seem archaic, but it is still useful.

Common Uses of Telnet

Telnet is a way to remotely connect to another computer system, with privileges

to run specific programs on that system.

Common uses of Telnet include:

Connecting to a system to use specific programs such as e-mail and statistics

applications.

Connecting to a networking device for information or configuration purposes

Connecting to an online database of information

Connecting to an online forum to interact and communicate with other users.

Using Telnet from a Command Line

The Telnet application uses a command-line interface, whether you launch it

from a DOS prompt or from a Windows icon.

Using Telnet with Windows 95/98/ME

To run Telnet from Windows 95,98 or ME:

1. From the Start menu, select Run then enter Telnet.The Telnet window opens.

2. Under the Connect menu, select Remote System. A connect dialog box

appears.

3. in the box market Host Name, enter the Telnet address for the Hawaii

state library system: Hawaii.lib.state.hi.us.

4. Click Connect once, or press ENTER to initiate the connection. The Telnet

Connectivity Screen appears.

5. At the “login:” prompt, enter the name of a Hawaiian island as your login

name.

Note: Important: After you log on to the remote site, pay attention to the

instructions that appear on screen to help you navigate in that particular

database. Menu options are usually easy to understand, but commands

vary from database to database. You can usually get help by typing help

or ? as you navigate.

6. To end you session, type exit or logout at the command line. You may

also go to the File menu and choose Close Connection.

Basic Telnet commands include:

Open – Establishes a connection to the specified host

Close – Closes an open connection and leaves you in the Telnet software

Quit – Closes any open Telnet sessions and exists the Telnet software.

Lesson 6 – Electronic Mail

Objectives:At the end of this lesson you will be able to:

Describe the key protocols used to transmit e-mail messages

E-mail is one of the most popular and widely used Internet applications.

Billions of e-mail messages are sent every day across the Internet. E-mail is a

fast and efficient way to communicate with anyone connected to the Internet,

from one person to thousands of people at a time. We can exchange files and

information with e-mail messages, and subscribe to e-journals and

newsgroups.

How does E-mail work?

E-mail is an asynchronous form of communication. That is, the recipient of

your message does not need to be available at the precise moment you send

it. This is a great convenience for both you and the recipient. In contrast, the

telephone, which is a synchronous communication medium, requires that both

you and your listener be on the line at the same time to communicate (unless

you can leave a voice message).

It is impossible to discuss all the details of the many e-mail packages

available to Internet users. However, most of these programs share basis

functionality that allows you to:

Send and receive e-mail messages

Save e-mail messages in a file

Print e-mail messages

Reply to e-mail messages

Attach a file to an e-mail message

There are many e-mail packages available for use in a TCP/IP network. First,

we will cover an important aspect of e-mail: interpreting Internet address.

Reading an Internet Address

To use Internet e-mail successfully, we must understand how names and

addresses for computers and people on the Internet are formatted.

Fortunately, Internet addresses are usually no more complex than phone

numbers and postal addresses. And, like those methods of identifying a

person, organization, or geographic location, Internet addresses have rules

and conventions for use.

An example of an Internet address is hr@gst.com. Internet addresses have

three parts as follows:

User name (hr in the example)

“At” sign (@)

Address of the user’s mail server (gst.com in the example)

The mail server’s address (e.g. gst.com) is called the domain name and is

based on the server’s IP address. Every server is connected to the Internet

has a numeric IP address. This IP address is composed of fours sets of

numbers separated by periods (e.g. the IP address for the mails server might

be 205.169.85.221).

Because it is easier for humans to remember names rather than numbers,

each server also has a corresponding domain name. This name associates

the server’s numeric IP address with a name that is easier to remember. Both

the IP address and domain name should work the same.

It is sometimes useful to read an Internet address or domain name from right

to left because this helps us determine information about the source of the

address. An address like 1234@gst.com does not tell us much about the

person who is sending us a message, but we can conclude that the sender is

affiliated with a commercial institution because of the suffix.com. The suffixes

of domain names loosely translate to the following conventions:

com – Commercial sites

edu – Educational sites

gov – Government sites in the United States

mil – Military sites in the United States

net – Network administrative organizations

org – Organizations in the United States not covered by the categories

above (e.g. nonprofit organizations)

biz – Commercial sites

info – Unrestricted use

There are some new domains that will be available:

name – For registration by individuals

aero – Air-transport industry

pro – Accountants, lawyers, and physicians

museum – Museums

coop – Cooperatives

Although there are variations in describing an Internet address, the @ symbol is

typically pronounced “at”, and the “.” (period) is pronounced “dot”.

E-mail Protocols

TCP/IP networks combine several protocols for implementing an e-mail network,

including:

Simple Mail Transfer Protocol (SMTP)

Post Office Protocol (POP)

Multipurpose Internet Mail Extensions (MIME)

Simple Mail Transfer Protocol

SMTP is an Application Layer protocol used to transfer mail across a TCP/IP

network. When e-mail is sent across a TCP/IP network, such as the Internet, it is

encapsulated in a SMTP header before traversing the network. An SMTP server

handles outgoing mail.

Post Office Protocol

POP is used to transfer information from a mail server to a user’s computer

where it can be ready by a mail program. Information is stored on a mail server

until it is downloaded to the client desktop. At the client desktop, the information

is read by an e-mail program such as Lotus Notes, Eudora, or Outlook.

Multipurpose Internet Mail Extension

MIME is used in conjunction with SMTP for supporting more than just standard

American Standard Code for Information Interchange (ASCII) text files.

Originally, SMTP only supported the transfer of ASCII files. Using MIME, many

different types of data can be sent by means of e-mail. Examples of other types

of data supported using MIME are:

Binary information

Graphic images

Video files

Audio files

Secure Multipurpose Internet Mail Extension (S/MIME) is a specification for

secure electronic messaging. In 1995, software vendors created S/MIME to solve

a very real problem: interception and forgery of e-mail. Protecting sensitive data

is a real concern, especially in a world becoming increasingly more connected.

The S/MIME specification was designed to integrate easily into e-mail and

messaging products.

Mail Server Configuration

The E-Mail Communication Diagram illustrates a typical e-mail configuration. The

components of this diagram are local mail clients, remote mail clients, and a mail

server.

The mail server is the computer that collects e-mail for all clients that use this

particular mail server. Each client must be configured to access the mail server.

In other words, the IP address of the e-mail server must be known by all e-mail

clients. Most mail servers today support POP, enabling each client on the

network to retrieve information on as needed basis. It is also important that the

mail server use MIME for transferring binary information.

Mail gateway software is used on the mail server for the purpose of sending e-

mail between different types of e-mail programs. Some e-mail programs use

SMTP, while others such as cc:mail, use proprietary e-mail protocols. Mail

gateways are only needed in systems that do not use SMTP.

Using E-Mail Clients

There are many e-mail clients, from those that read only text, to GUI clients that

read HTML and display graphics and animations. This section details some

issues to be aware of when communicating through e-mail messages. These

issues include “netiquette” e-mail privacy and signature files.

Configuring E-Mail Clients

There are many Internet e-mail clients available for use across many different

operating systems; space does not allow us to address them all. Instead, we will

discuss the procedures necessary to configure Microsoft’s Outlook Express to

send and receiver e-mail from an SMTP/POP mail server.

Outlook Express

To configure a new account in Outlook Express, from the main menu, select

Tools > Accounts. sIn the Internet Accounts window, click the Add button and

select Mail. The Outlook Express Client diagram illustrates the Outlook Express

client Internet Accounts configuration window.

The Internet Connection Wizard appears. Follow the wizard prompts to enter an

account Display name, followed by the account’s e-mail address. Once these are

entered, the Internet Connection Wizard prompts for the incoming and outgoing

mail server information.

The wizard prompts for the incoming mail server protocol type. The options are

POP3, Internet Message Access Protocol (IMAP), and HTTP. Choose the POP3

server type from the pull-down menu, then enter the incoming and outgoing mail

server IP addresses or names. In this example, we entered the server name

mail.msn.com. the outgoing server type is always SMTP.

The next window prompts for your user name and password. The final step is to

select Finish to complete the client setup.

When you connect to the Internet to download new e-mail messages, the

incoming server validates the user name and password. You may configure the

client to download e-mail periodically. Each time the client request new

messages, it passes your user name and password to the incoming server. The

outgoing mail server does not require a user name and or password; it accepts

mail on the client’s behalf without the need for account credentials.

Netscape Messenger

The process for configuring Netscape Messenger is similar to the process for

Outlook Express. In Netscape Messenger, start from the main menu and select

Edit > Mail/News Account Settings. Click the New button to access the Account

Wizard. Follow the wizard prompt to set up your e-mail account.

E-mail Privacy

The need for corporate security has led to increased monitoring of employee

communications and computers. It is a fact that one of the largest security risks

for companies is intentional of unintentional security breaches by employees.

The need to secure computer systems has encouraged the development of many

different monitoring and encryption technologies.

As an employee, you should understand that your company has the right to read

you e-mail messages, listen to your voice mail, and access the files in your

computer, since the devices that produce them are the company’s property.

The issue of privacy on the Internet is still ambiguous and will probably be

resolved through various court cases in the future. The 1986, Electronic

Communications Privacy Act (ECPA) extends the federal wiretapping statute to

cover electronic communications. This law hinges on whether employees have a

“reasonable expectation of privacy” in the workplace.

This is why most companies have a written policy that details security issues and

privacy rights. These policies generally state the need for security outweighs

concerns about personal privacy, and the courts have supported this notion in

most cases.

Signature Files

An e-mail signature is usually a text file that you create, and that appears at the

end of messages that you send. This eliminates the need for you to “sign off” at

the end of every message. Signature files can include any of the following: your

name, title, physical or e-mail address, a link to your Web site, or a phrase that

describes your philosophy. You can put as much or as little information on a

signature file as you want people to know about you.

Internet Outlook

To create or edit a signature file in Outlook, select Tools > Options from the main

menu. In the Options window, select the Mail Format tab. Within the Mail Format

tab, click Signature Picker at the bottom right. The Signature Picker Screen

appears.

In the Signature Picker window, you can select an existing signature to edit, or

you can create a new signature by clicking New.

Netscape Messenger

Netscape Messenger does not allow you to create a signature file, so you can

create the file in a word processor and save it as a text file. Within Messenger,

you navigate to the location of the file.

To attach an existing signature file, select Edit > Preferences from the main

menu. In the Preferences window, double-click the Mail and Newsgroups

category. Under Mail and Newsgroups, select Identity. The Identity information

appears in the right side of the window. In the Identity portion of the window,

select Choose to navigate to an existing signature file. You can attach or edit a

vCard as your signature.

New Accounts

You can configure your e-mail client to receive newsgroup messages from some

newsgroups. At one time, e-mail was the primary method that people used to

access newsgroups, but now many of the free newsgroup sites allow you to view

the messages only through a browser. An example of this trend is Google

Groups (http://groupsgoogle.com)

There are several sites that list news servers that you can subscribe to through

your e-mail client. One good site is http://www.newzbot.com. When you find a

server that interest you, follow the directions in the following sections, depending

on which browser you use.

Configuring Outlook

To configure a news server, from the main menu select Tools > Accounts. In the

Internet Accounts window, select the News tab. Click on the Add button and

select News to start the Internet Connection Wizard.

The Internet Connection Wizard asks you a series of questions. Follow the

directions to enter your user name, e-mail address, and news server IP address

or name. Click Finish to complete the wizard setup. In the Internet Accounts

window, you will see your new account listed in the News accounts:

Click Close and a message will appear, asking if you want to download the

available newsgroups form the news sever. Click OK. It may take a few minutes

to download the newsgroups. When the download is complete, click on the

groups(s) you are interested in, and click Subscribe. Click OK to exit. You will

see that your newsgroup is listed as a folder. Click on the newsgroup folder to list

the current messages.

Configuring Netscape Messenger

To configure a news server, from the main menu select Edit > Mail/News

Account Settings. In the Account Settings Window, Click New Account, which

opens the Account Wizard. Follow the wizard instructions to select a newsgroup

account, and enter your user name, e-mail address, and news server IP address

or name. Click Finish to complete the wizard setup. In the Account Settings

window, you will see the new account in the list of accounts. Click OK to close

the Account Settings window. Now you can subscribe to one or more

newsgroups on the server account you just added. To subscribe, from the main

menu, select File > Subscribe, which opens the Subscribe window. In the

Subscibe window, select the Server that you just added. The available

newsgroups will download (this may take a few minutes). From the available

groups, select one that interests you and click Subscribe. A check mark appears

next to the selected newsgroup.

Click OK to close the Subscribe window. The newsgroups you subscribed to

appear as folders in Netscape Messenger. Click on the newsgroup folder to list

the current messages.

Netiquette

“Netiquette” is a term that refers to etiquette in Internet communications. These

communication forms include personal and business e-mail, mailing lists, and

chat applications. Since online communication is so quickly and easy, people

tend to use an informal style. The following list outlines some issues to keep in

mind when sending messages over the Internet:

Anything you write may be forwarded to anyone. Use a professional tone and

language when sending messages from work.

Your employer may have rules and standards about communication over

company servers. Educate yourself about the company’s policy.

The company you work for has the right to read whatever is sent over its

equipment.

Proofread your messages before you send them. Make sure that your

message says what you mean.

Spell checkers are standard in most e-mail applications. Use them to make

sure your messages are readable and professional.

References:

1. Westnet Learning Technologies (2002).Internet Technologies. Singapore: Thomson Course Technology

2. Gary P.Schneider and Jessica Evans (2002). The Internet (3rd Ed) United States: Thomson Course Technology.

3. Gary B.Shelly, Thomas J.Cashman & Misty E.Vermaat (2007) Discovering Computers 2007: A Gateway to Information, Web Enhanced Complete. USA: Thomson Course Technology