Transcript File

Principals of Information Technology
Networks and Hackers
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Copyright © Texas Education Agency, 2011. All rights reserved.
Computer System:

A basic computer system is made up of
two parts, Hardware (physical equipment
that you can touch), and Software
(programs installed on the computer).
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Computer Networks:

Computer Networks allow users to connect over
distances. They allow file sharing, hardware
sharing, and instant communication, making
them a necessary tool for offices, schools and
homes all over the world.

A computer network consists of several
components, each of which is important to
making the network function correctly as a
whole.
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Network:
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PARTS OF A NETWORK
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Workstations:

These are known as Desktop Computers.
The computer you use at home or school
would be called a Workstation in a Network.
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Servers:

Servers can look like Desktop Computers; however most
do not look like your “normal” computer. Servers do not
really need monitors, graphics and sound cards. What
they really do need is Hard Drives. In most schools,
when you save your work, you are saving to a server. By
doing this, you can access your school work from any
computer that is on your school network.
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Modems:

A modem is a device that enables computers
to interpret data they receive from a network,
or send data in the proper form along a
network.
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Hubs:

A Hub is sort of like a car radio.
Every computer that has that
section of network (like a radio
station) can hear everything that is
being transmitted. All the computers
that are connected to that hub
receive all the information that goes
through it. Usually if you have a
hub, you also have a router.
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Switches:

A switch is more complex than a Hub and works a lot like
a two-way radio. In a room full of people, only the person
holding the other radio can hear what is being said. It
keeps track of which computers are where and when
something comes in, it sends it only to that specific
computer, not every computer on that section of the
network. It is more secure than a hub, and faster than a
hub, but not as powerful as a router.
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Routers:


Routers work a lot like a telephone system. Each
computer is given its own unique number by the router.
When information comes into the router, it is then sent
along to the correct number, or in this case, computer.
There are more options built into routers than there are
available to switches. A router can have the equivalent
phone options of call screening and caller id. This is
beyond a switch’s capabilities.
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Routers
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PEER TO PEER NETWORKS
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Peer to Peer Network:

This is a type of network where the
computers in the network share resources
among each other.


Every computer on this network is equal; all the
computers run the same networking software and
file systems for sharing.
Printers, Scanners and other external devices are
shared by the machine they are plugged into,
otherwise known as managed by.
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Peer to Peer Network
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Pros for a Peer to Peer Network

Advantages:

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It is less expensive to set up a Peer to Peer
network initially.
You may already own the software needed to
get a peer to peer network setup.
This type of network does not require the
installation of dedicated server hardware or
expensive security software.
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Cons for a Peer to Peer Network

Disadvantages:

If you have a Peer to Peer Network you need to be aware that
shared resources, such as printers, place a special demand
on the computers in the network.

Also, due to the nature of this type of network, all of the
computers on the network provide access to all of the
machines resources. The down side of this is that you can
unintentionally expose private files to all the other users on the
network.

There is also no data security or protection from hackers,
viruses, etc.
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Peer to Peer Operating Systems

In the Peer to Peer Network Operating
System, each of the workstations has an
operating system that tells it how to store and
share resources with the others.

The two software packages that allow this
type of network are called Appleshare (for
MACs) and Windows for Workgroups (for
PCs)
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CLIENT SERVER NETWORKS
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Ethernet

Ethernet is a type of connection between computers that
forms the basis of most LANs.

It also serves as one of the main methods for connecting
a computer or network to an Internet hub.

The origin of Ethernet was the idea of connecting several
computers together in a network via coaxial cables;
since that time it has evolved into a much more
sophisticated system that uses specialized Ethernet
cables that connect to a central hub or router in order to
network several computers together.
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Ethernet
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LAN

LAN stands for Local Area Network.

A Local Area Network is a group of
computers that are linked together that share
internet access, file access, applications,
storage, and allow connected computers to
share printers and scanners.
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LAN Issues:

For a LAN to work properly, a router must be
installed on the primary computer that is
connected to the internet. Each computer
connected to the LAN must have an Ethernet
card installed.

The other issue with a LAN is that they are
usually confined in a single building.
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WAN


WAN stands for Wide Area Networks.
A WAN is a collection of regular local area
networks that are all interconnected together
to form one giant network. Oftentimes,
schools and even large companies will
operate a WAN on premises.
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WANs Continued

Advantages:
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
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Flexible Access: School networks can be created for
students to access files throughout the school district.
Speed: Networks speed up the file sharing and saving
process.
Disadvantages:


Expensive to Install: WANs save money over time, but
are expensive to set up at first.
Time: WANs require maintenance of the network
which costs both money and time.
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Token Rings


Token Rings work by sending data from one
machine to the next, and so on, around a ring
until it ends up back where it started.
It also uses a special token passing protocol
which means that a machine can only use the
network when it has control of the Token; this
ensures that there are no collisions because
only one machine can use the network at any
given time.
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Token Ring
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Token Ring Issues

In order for Token Rings to work,

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All computers must check for lost or duplicate
tokens.
All connected computers must “Vote” a new
leader to create a new token.
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Client/Server Operating Systems

Client/Server set up allows the network to
centralize functions and applications in one or
more file servers.


File servers become the “heart” of this system and
provide access to files and resources, as well as
providing security.
Workstations have access to the resources to files
on the file servers.
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Client/Server Operating Systems

There are many different softwares out there
for this type of network. The most popular
ones are:




Macintosh OSX
Microsoft Windows Server
Novell
UNIX
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Client/Sever Operating Systems

Advantages:


This type of network makes it easy to install new
technology and new elements.
The server can be accessed remotely and you
can have both MACs and PCs on the network.
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Client/Sever Operating Systems

Disadvantages:



Client/Servers depend on their servers. When
they go down, the network will no longer work.
There is a hefty investment for a client/server
network. It pays off in the long run, but does
require money to set it up.
Large networks will require dedicated staff to
maintain a client/server network, and to work out
the “kinks” when problems arise.
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NETWORK THREATS
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Hackers

A computer Hacker is someone who finds
access in a computer’s security system to
break into another machine.

Hackers usually collect information on the target
computer and then try to find access into the
computer system.
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Security Threats

The most common threats are:




Spam: this is unwanted commercial e-mail.
Viruses: can cause your computer to slow down,
or even destroy your hard drive.
Adware/Malware: this is software that gets
installed on the computer. It can cause annoying
pop-ups or even steal information.
Information Threats: where hackers steal
important information: client information, back
account numbers, etc.
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Hackers

Networks can take steps to protect their
networks. The most common are:


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Installing a firewall
Advising caution on the net
Making sure that the network is password
protected, especially if using a wireless
network.
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