Computer Network


Computer Network is a way to transfer data from one computer to another.
Computer Network is an engineering , discipline conversion with communication between computer system or device.

Types of Networks – :


LAN(Local Area Networking)
WLAN(Wireless Local Area Networks)
WAN(Wide Area Networks)
MAN(Metropolitan Area Networks)
CAN(Campus Area Networks)
SAN(Storage or Sytem Area Network)
PAN(Personal Area Network)
Dan(Desk Area Network)
Let’s talk about these types of
networking in detail:

LAN(Local Area Networking)-:


Local Area Networking is used
primarily in small areas such as
schools, hospitals and office buildings.
Local Area Networking, is one of the
older types of networks. TCP/IP is used
as the method of communication
between computers in Local Area
Networking. Due to its small size, it is
possible for one person to administrate
a Local Area Network. Local Area
Networks are viable to quick change,
using a bus network topology that
allows for easy access to the Local Area

WLAN(Wireless Local Area Networks)-:


Wireless Local Area Networks are much
like LAN networks, except they do not
require network cables to connect each
other. Radio and infrared signals are
used to communicate between
machines whilst using a wireless local
area network. Wireless Local Area
Networks allow for small amounts of
mobility whilst being connected to the
internet. Wireless Local Area Networks
work according to the IEEE 802.11
standards. Wireless Area Networks are
commonly seen being used by a WiFi
internet connection . Wireless LAN
connections offer a surprising amount
of mobility for users with laptops and
smart phones while being able to stay
connected to the internet by different
networking topology .

WAN(Wide Area Networks)-:


Wide Area Networks are used to
connect server machines and
computers across continents are
countries for constant information
updates. Wide Area Networks, are used
across the globe, many networks
connect with one another across
continents to create one giant Wide
Area Network. Wide Area Networks use
optic fibre as their communication
medium. The largest example of a Wide
Area Network is the internet itself,
which connects all users to the
information and data that is available
on the the internet.

MAN(Metropolitan Area Networks).


Metropolitan Area Networks are not
commonly used these days, they are
used to create communication between
systems in an entire city. Hence a
Metropolitan Area Network area falls
between the sizes Local Area Networks,
and Wide Area Networks. Metropolitan
Area Networks are used by city specific
businesses such as the New York Times
in the state of New York.

CAN(Campus Area Networks).


Campus Area Networks are usually a
connection of many small LAN
networks which are often used on
university campuses and office
buildings. Campus Area Networks allow
for easy file sharing between different
departments as all the files are usually
shared on the server machines of each
LAN network. This type of network
offers a lot of simplicity in the transfer
and downloading of files.

SAN(Storage Area Network).


Storage Area Networks are primarily
used as information databases. They
are not usually used by large
organizations or similar entities. They
are specifically used for the storage of
information, and easy retrieval of
specific pieces of data whenever
required. Storage Area Networks are
usually used by websites which offer
downloading services.

SAN (System Area Network)


System Area Networks are speed
oriented networks which provide high
speed internet connections to a cluster
of computers. These are primarily used
for server purposes, and allow other
computers to connect to these System
Area Networks. Permission to different
access points are given according to
what status a system is on the System
Area Network, such as administrators
or simple users.

Penetration testing & What is Vulnerability?

Penetration testing is an attack on computers system with the intention of finding security weakness, potentially gaining access to it and it’s functionality & data’s.

Vulnerability – :
In computer security, a vulnerability is a weakness which allows attacker to reduce system information assurance.

Ethical Hacker


An Ethical Hacker is
usually employed with the organization
and can be trusted to undertake an
attempt to penetrate networks and/or
computer systems using the same
methods as a Hacker. The goal of the
ethical hacker is to help the
organization take pre-emptive measures
against malicious attacks by attacking
the system himself; all the while staying
within legal limits. In order to become
an Ethical Hacker or Security Expert one
must think out of the box with the
mentality that in order to catch a thief.


Ethical Hacker is an computer and network expert who attacks a security system on behalf of its owner.

Ethical Hacking is also known as penetration testing, intrusion testing and red teaming.

Introduction to Information Security

Means any data it can be in any format like text or any kind of documents, audio etc.


How to protect that data from unauthorised person or hackers.


¶Attributes of Information Security ¶

Integrity and
Availability (CIA)

What is it?
You may have heard
information security
specialists referring to
the “CIA” — but
they’re usually not
talking about the
Central Intelligence
Agency or the Culinary
Institute of America.
CIA is a widely used
benchmark for
evaluation of
information systems
security, focusing on
the three core goals
of confidentiality,
integrity and
availability of
Each time an
information technology
team installs a
software application
or computer server,
analyzes an data
transport method,
creates a database, or
provides access to
information or data
sets, CIA criteria must
be addressed.
As a user of medical
campus systems, you
are a critical part of
the team too. CIA
depends on you
being a knowledgeable,
safe user of campus
information resources.

Confidentiality refers
to limiting information
access and disclosure
to authorized users —
“the right people” —
and preventing access
by or disclosure to
unauthorized ones —
“the wrong people.”

methods like user-IDs
and passwords, that
uniquely identify data
systems’ users and
control access to data
resources, underpin
the goal of
Confidentiality is
related to the broader
concept of data
privacy — limiting
access to individuals’
personal information.
In the US, a range of
state and federal
statutes, with
abbreviations like
HIPAA, set the legal
terms of privacy.

Integrity refers to the
trustworthiness of
information resources.
It includes the concept
of “data integrity” —
namely, that data have
not been changed
whether by accident or
deliberately malign
activity. It also
includes “origin” or
“source integrity” —
that is, that the data
actually came from the
person or entity you
think it did, rather
than an imposter.
Integrity can even
include the notion that
the person or entity in
question entered the
right information —
that is, that the
information reflected
the actual
circumstances (in
statistics, this is the
concept of “validity”)
and that under the
same circumstances
would generate
identical data (what
statisticians call
On a more restrictive
view, however,
integrity of an
information system
includes only
preservation without
corruption of whatever
was transmitted or
entered into the
system, right or

Availability refers,
unsurprisingly, to the
availability of
information resources.
An information system
that is not available
when you need it is
almost as bad as
none at all. It may be
much worse,
depending on how
reliant the
organization has
become on a
functioning computer
and communications
A modern medical
center has a near-
total dependency on
functioning information
systems. We literally
could not operate
without them.
Availability, like other
aspects of security,
may be affected by
purely technical issues
(e.g., a malfunctioning
part of a computer or
device), natural
phenomena (e.g., wind
or water), or human
causes (accidental or
While the relative risks
associated with these
categories depend on
the particular context,
the general rule is that
humans are the
weakest link. (Again,
that’s why your ability
and willingness to use
our data systems
securely is critical.)
Prevention vs.
Security efforts to
assure confidentiality,
integrity and
availability can be
divided into those
oriented to prevention
and those focused on
detection. The latter
aims to rapidly
discover and correct
for lapses that could
not be — or at least
were not —
The balance between
prevention and
detection depends on
the circumstances,
and the available
security technologies.
For example, many
homes have easily
defeated door and
window locks, but rely
on a burglar alarm to
detect (and signal for
help after) intrusions
through a
compromised window
or door.
Our information
systems use a range
of intrusion prevention
methods, of which
user-IDs and
passwords are only
one part. We also
employ detection
methods like audit
trails to pick
up suspicious activity
that may signal an