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There are three (3) essential items required
to use the Internet for the average person.
 A. Some
form of computer.
B. Some
type of connection to the Internet.
C. The
correct software (Browser and/or E-mail agent).
The different types of computers are
almost unlimited. Even older computers that do not have graphics
can get onto the internet. PCs and Macs are probably the most common.
There are several forms of connection
to the Internet. Almost all of them require the cooperation of an
ISP to actually make the connection to the Internet Backbone (main
Internet data channel). Most individuals make a connection from
their local computer to their ISP through a phone line and some
form of modem (dialup, ISDN, or DSL).
There are many forms of software available
that perform many different functions. The two most common are a
Browser and E-mail client/agent.
1. The Browser creates a window on your
local computer to view web pages. Web pages are actually computer
programs. They are written in HTML (Hypertext Markup Language).
The browser program is responsible for converting HTML commands
into a picture that you can view on your computer. A browser is
also responsible for converting your keyboard or mouse input into
something the web page can understand. When a person enters a web
address, the browser sends the address out to the host and requests
a DNS lookup. The DNS server looks up the address of the website
and then directs the browser to that site where a request is made
for a page. The host at the site then sends the program for that
page back to the browser, where hopefully it can be viewed. Within
the web page there may be type, pictures, links to other pages,
tables to be filled in by the visitor, etc.
"A browser is not a browser is
not a browser!" Not every browser (even different versions
of the same browser, and even the same browser on different computers)
converts the web page HTML commands the same way. The same web page
may look very different on one computer as compared to another.
This is especially important to keep in mind when creating your
web pages. More on this later.
2. The e-mail agent or client is a program
that follows at least one of a number of set criteria for retrieving
e-mail from your box (POP3 mail boxes, not MSN HOT MAIL, or AOL
mail, etc. mail). When e-mail is sent to you, your ISP stores that
message in a mail box at the ISP's post office for you. When you
start your e-mail client or agent program, it effectively sends
a messenger from your computer to the ISP's post office. The messenger
looks in your mail box and makes a copy of any messages there and
returns the copies to your computer. EVEN
IF YOU DO NOT OPEN THE INDIVIDUAL MESSAGES, you still have
received your mail and it is on your computer. Depending on the
settings of your e-mail client/agent, once the messenger has returned
with the copied mail, it may send a message back to the post office
to delete any mail in your box.
What is opened and unopened mail seems
to be a little confusing. Most of the e-mail agents/clients have
what they call a preview window. Just highlighting a message will
cause the e-mail program to display the message in a preview window.
In some programs, this counts as opening your message and in others
it does not. In some programs, you must actually select the message
and open it into it's own window to officially open the message.
So who cares?
Who cares? Everyone who reads e-mail
should care. E-mail is the most common way to spread a computer
virus. There are two common methods used to spread a virus via e-mail.
One way is to attach a program as an "attachment" that
is activated by the user when the attachment is opened. The second
way is via something called "embedded macros". An embedded
macro is a little program that is entered as part of the actual
message. It is essentially a program that runs when the message
is viewed. BOTH OF THESE METHODS CAN PUT
A VIRUS ON YOUR COMPUTER! The preview window almost never
actually opens an attachment unless it is a known format picture.
However, macros can be run by your program just by putting it in
the preview window. You can start turning various functions off,
thereby preventing things like macros from running. However, this
may also prevent you from viewing parts of your message. If you
are going to get e-mail, you should check out some form of virus
protection software packages. These packages are not perfect, but
they help!
Just
a note. Recently, a Internet security company was looking for weaknesses
to viruses in various programs. They found a really neat one in
Microsoft Outlook and Outlook Express 5.0 (later, similar weakness
were found in Netscape 4.x). This weakness allowed a virus to be
downloaded to your computer simply by having the messenger go and
get a copy of your mail and return it to your computer.
THE VIRUS WOULD TAKE HOLD EVEN IF YOU NEVER OPENED OR EVEN VIEWED
YOUR MAIL! Version 5.5 fixed
this problem (free upgrade to everyone, but a long download!. "http://www.microsoft.com/windows/ie/default.htm"
and follow directions)
© 2001 - Barry
Wroobel - Discovery Data Systems, inc.
(note: Set left and right printer margins
to 0.25" for printing)
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