Download Session2

Content

Overview of Computer Networks (Wireless and Wired)

IP Address, MAC Address and Workgroups

LAN Setup and Creating Workgroup

Concept on typical Servers (Proxy, DNS, Web, Mail)

File, Folder, Printer, Scanner Sharing over LAN

Browser Configuration and Internet Options

File download and popup unblock

Internet virus, spyware, malware, spam

Searching in the web

E-mail
Computer Networks

Computer network connects two or more autonomous
computers.

The computers can be geographically located anywhere.
Overview of Computer Networks
(Wireless & Wired)

Connection among computer for Information/ data and resource sharing.

Wireless and Wired

A popular example of a computer network is the internet, which allows millions of
users to share information

Computer networks can be classified according to their size:

Local Area Network (LAN)

Metropolitan Area Network (MAN)

Wide Area Network (WAN)
LAN, MAN & WAN

Network in small geographical Area (Room, Building or a
Campus) is called LAN (Local Area Network)

Network in a City is call MAN (Metropolitan Area
Network)

Network spread geographically (Country or across
Globe) is called WAN (Wide Area Network)

Also know as Internet
Applications of Networks

Resource Sharing



Information Sharing





Easy accessibility from anywhere (files, databases)
Search Capability (WWW)
Communication


Hardware (computing resources, disks, printers)
Software (application software)
Email
Message broadcast
Remote computing
Distributed processing (GRID Computing)
Networking Media



Networking media can be defined simply as the means by
which signals (data) are sent from one computer to
another (either by cable or wireless means).
Wireless
Wired
IP Address, MAC Address and Workgroups

IP Address- a unique number which identifies a computer and its location on the internet.
Like mobile number

32 bits (4 bytes) in length (0-255)

MAC Address- Media Access Control address is a unique identifier assigned to most
network adapters or network interface cards (NICs) by the manufacturer…

Workgroups- like room
Local Area Network (LAN)

A LAN is a network that is used for communicating among computer devices,
usually within an office building or home

LAN’s enable the sharing of resources such as files or hardware devices that may be
needed by multiple users. (printer, scanner sharing)

Two types of LAN: server-client base, simple

LAN Setup

Hardware: NIC Card, UTP Cable, RJ 45 connector

Two steps


IP address assigning

Workgroup creating
Start  Control Panel  Network Connections Create a new connection
IP address assigning

Right click on the 'My Network Places' icon that has now appeared on your desktop and
select 'Properties'.

Then double click on 'Local Area Connection' to get to this screen:

and then select Properties to arrive here:
Use the following an IP
address
Selected
IP Address
192.168.1-254.1-254
Subnet Mask
255.255.255.0
File, Folder, Printer, Scanner Sharing over LAN
Lets see
Concept on typical Servers (Proxy, DNS, Web, Mail)


Proxy Server

Server that stands between an external network (such as Internet) and an organization's internal
(private) networks and serves as a firewall.

It prevents external users from directly accessing the internal information resources, or even
knowing their location.

Server that stores frequently requested information (documents or files) from elsewhere in the
network and makes it available to the users. While this arrangement results in higher access
speed.

It is possible to filter unwanted website (nude or adult website).

A proxy server improves Internet access speeds from a network primarily by using a caching
system.

When we use internet through proxy server then we need to configure our web browser by
setting proxy IP
DNS Server:

Converting/mapping web address to IP address. www.google.com  152.76.93.12

Web Server: hold website/ webpage (http protocol)

Mail Server: for email (POP3, SMTP protocol)
Browser Configuration and Internet Options


Home page adding

Firefox menu Options  Options  General (for Mozilla Firefox Browser) (New version)

Or menu  tools  Options  General
Popup unblock

Firefox menu Options  Options  Content (for Mozilla Firefox Browser)

Font Size

Proxy setup: menu  tools  Options

 Advance  Network  Settings


(manual proxy configuration)

192.168.1.1 (Proxy server address)
JavaScript block/ unblock

menu  tools  Options  contents
Internet virus, spyware, malware, spam

A computer virus is a harmful program that is secretly introduced into a system in order
to corrupt it or destroy data. Its has self replication and spread capability.

Malware, short for malicious software, is a software designed to harm or secretly access
a computer system without the owner's informed consent.

Spyware is a type of malware that can be installed on computers, and which collects
small pieces of information about users without their knowledge. The presence of
spyware is typically hidden from the user, and can be difficult to detect.

A worm is a self-replicating malware program, which uses a computer network to send
copies of itself to other nodes and it may do so without any user involvement. Unlike a
computer virus, it does not need to attach itself to an existing program. Worms almost
always cause at least some harm to the network, even if only by consuming bandwidth,
whereas viruses almost always corrupt or modify files on a targeted computer.

Adware, or advertising-supported software, is any software package which automatically
plays, displays, or downloads advertisements to a computer.
??