Type of Website

PORTAL

A web site that offers variety of internet services from single, convenient location.

Example : Yahoo.com, MSN.com

BUSINESS

Contains content that promotes or sells products or services.

Example : Zalora, Shopee

BLOG

An informal web site consisting of time-stamped articles, or posts in a diary or journal format, usually listed in reverse chronological order.

Example : Blogspot

WiKi

A collaborative web site that allows users to create, add to, modify, or delete the web site content via their web browser.

Example : WiKipedia

Online Social Network

Encourages members in its online community to share their interests, ideas, stories, photos, music and videos with other registered users

Example : Facebook

Internet Address

What is Internet Address

• A number that uniquely identifies each computer or device connected to the Internet.

• IP addresses are also referred to as IP numbers and Internet addresses.

• IP address sometimes is called a dotted decimal number or dotted quad.

IP Usage

• A way to find specific server or computer on the internet or a network

• Provide identity to a computer in a network

• Identify for a particular device/machine on a particular network

• Allows transfers of files and e-mail

IP Structure

• IP addresses usually consists of four groups of number each separated by a period.

• The number in each group is between 0 and 255.

• It is 32 bit long ,each group is 8 bits long

• Commonly written in decimal.

• Written, for example, 128.35.0.72

• These four sections represent the machine itself and the network it is on

• The network portion is assigned.

• The host section is determined by the network administrator

 Reserved IP

IP Addresses

Two versions of the Internet Protocol (IP) are in use:

•  IP Version 4 (IPv4) 
•  IP Version 6 (IPv6)

IP Version 4 (IPv4)

• IPv4 an address consists of 32 bits which limits the address space to 4294967296 (232) possible unique addresses.

                      https://commons.wikimedia.org/wiki/File:Ipv4_address.svg

IP Version 6 (IPv6)

• The address size was increased from 32 to 128 bits or 16 octets.
• Provides the potential for a maximum of 2128, or about 3.403×1038 unique addresses.

https://commons.wikimedia.org/wiki/File:Ipv6_address_leading_zeros.svg

Domain Name and IP Addresses

An Internet Protocol, or IP, address is different than a domain name. The IP address is an actual set of numerical instructions. It communicates exact information about the address in a way that is useful to the computer but makes no sense to humans. The domain name functions as a link to the IP address. Links do not contain actual information, but they do point to the place where the IP address information resides. It is convenient to think of IP addresses as the actual code and the domain name as a nickname for that code. A typical IP address looks like a string of numbers. It could be 232.17.43.22, for example. However, humans cannot understand or use that code. To summarize, the domain name is a part of the URL, which points to the IP address.

Internet Service Provider

Dial up Connection

1. Coventional dial up

PC has to dial via phone line to connect
Characteristics of Coventianal dial up:
               ➧Slower,but cheaper
               ➧Ties up phone lines
               ➧EXAMPLE: TMNet
      2. ISDN- Transfer data over ordinary telephone lines
Typically uses two phone lines to transfer data
Characteristics of ISDN:
              ➧Faster, but pricey
              ➧Doesn't tie up phone line
              ➧Used by businesses and individuals


Direct Connection/Broadband Internet Connection

• DSL(Digital Subscriber Line)

Transmit over telephone lines but does not tied up the line
Example : TMnet

• Cable Internet Service/Cable Modem

Internet access through the cable television network via cable modem

• Fixed Wireless

Uses radio transmission towers rather than satellites
Example : YTL

• Wi-Fi

Data is transmitted through radio waves
Example : TMNet

• Satellite Internet Service

Broadband option for rural area
Example : Parabola

• Fiber to the Premises(FTTP)

Uses fiber-optic cable to provide high speed internet access often via a modem
Also known as Broadband over Fiber(BoF)
Example : TMNet

• Cellular Radio Network

Internet connections to devices with built-in compatible technology or computers with wireless modems
Also known as Mobile wireless
Example : Celcom,Maxis,DiGi

WORLD WIDE WEB

• Web Pages

        -Each electronic documents on the Web.
        -Can contain text, graphics, animation, audio, and video.


Types of Web Pages

1.         Static (fixed) : A fixed Web page where visitors all see the same content.
2.         Dynamic (changing) : A Web page that allows visitors to customize some of all the                    viewed content

• Web Browser

A Web browser or browser is application software that allows users to access and view Web pages.
The purpose of Web browser is to bring information resources to the user.
With an Internet connection established, you start a Web browser.
The browser retrieves and displays a starting Web page.

• Web Adress

A  Web page has a unique address called a URL (Uniform Resource Locator) or Web address.
Web browser retrieves a Web page using its web address.
Web address consists of :

1.          Protocol
2.          Domain name 
3.          Path
4.          Web page name

Example : http://www.kmph.matrik.edu.my/fizik/index.html

•          Protocol             : http://
•          Domain name    : www.kmph.matrik.edu.my
•          Path                   : fizik
•          Web page name : index.html

• Web page navigation

Most Web pages contain hypertext ot hypermedia links
Hypertext : Links in text-based documents
Hypermedia : Combines text-based links with graphic, audio and video links.

•  Web searching

A primary reason that people use the Web is to search for specific information, including text, pictures, music and video.
The first step in successful searching is to identify the main idea or concept in the topic about which you are seeking information.

Types of Computer Security Risk

MALICIOUS CODE.

A computer virus is a potentially damaging computer program that affects or infects a computer negatively by altering the way the computer works without the user's knowledge or permissions.

Differences of Malicious Code.

• Computer virus.

Attached itself to a program or file which cannot spread without human action.

When we run or open a file in which virus is present then it starts effecting and starts spreading.

• Worm.

Worm is similar to virus but spreads without human action.

It gets multiplied or copied itself into hundred or thousands in number.

Spread itself into other computers through mail or address box.

• Trojan Horse.

Similar to virus and worm but it does not spread or reproduce

It looks similar to a software but will actually damage once installed or run it.

Can cause severe damage such as deleting files.

• UNAUTHORIZED ACCESS AND USE.

                                         

Unauthorized access is when someone gains access to a website, program, server, service, or other system using someone else's account or other methods. For example, if someone kept guessing a password or username for an account that was not theirs until they gained access it is considered unauthorized access.Unauthorized access could also occur if a user attempts to access an area of a system they should not be accessing. When attempting to access that area, they would be denied access and possibly see an unauthorized access message.

Some system administrators set up alerts to let them know when there is an unauthorized access attempt, so that they may investigate the reason. These alerts can help stop hackers from gaining access to a secure or confidential system. Many secure systems may also lock an account that has had too many failed login attempts.

• HARDWARE THEFT

  

Hardware Theft- is the act of stealing computer equipment. Hardware Vandalism- is the act of defacing or destroying computer equipment.

• SOFTWARE THEFT.

     

Software theft. (legal) The unauthorized duplication and/or use of computer software. This usually means unauthorized copying, either by individuals for use by themselves or their friends or, less commonly, by companies who then sell the illegal copies to users.

• INFORMATION THEFT

        

Information theft occurs when someone steals personal or confidential information. If stolen, the loss of information can cause as much damage as hardware or software  theft.

• SYSTEM FAILURE.

A system failure can occur because of a hardware failure or a severe software issue, causing the system to freeze, reboot, or stop functioning altogether. A system failure may or may not result in an error being displayed on the screen. The computer may shut off without warning and without any error message. If an error message is displayed, it often is displayed as a Blue Screen of Death error.

Risk of Security Measure

• DATA BACKUP.

Is the result of copying or archiving files and folders for the purpose of being able to restore them in case of data loss.

• CRYPTOGRAPHY.

                                   

Technology of encoding information so it can only be read by authorized individuals.

• ANTI-VIRUS

                            

Anti-virus software is a program or set of programs that are designed to prevent,search for, detect and remove software viruses and other malicious software like worms, viruses,trojan horse adware, and more.

• ANTI-SPYWARE

                                

A typed of malware that is installed on a computer without the user's knowledge in order to collect information about them.

• FIREWALL

                                

In computing, a firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules.[1] A firewall typically establishes a barrier between a trusted internal network and untrusted external network, such as the Internet.[2]

Firewalls are often categorized as either network firewalls or host-based firewalls. Network firewalls filter traffic between two or more networks and run on network hardware. Host-based firewalls run on host computers and control network traffic in and out of those machines.

COMMUNICATIONS DEVICE AND TRANSMISSION MEDIA

TYPES OF COMMUNICATION DEVICE

A communication device is a hardware device capable of transmitting an analog or digital signal over the telephone, other communication wire, or wirelessly. The best example of a communication device is a computer Modem, which is capable of sending and receiving a signal to allow computers to talk to other computers over the telephone. Other examples of communication devices include a network interface card (NIC), Wi-Fi devices, and an access point.

• Dial-up Modem

A communications device that can convert digital signals to analog signals and analog signals to digital signals, so that data can travel along an analog telephone line.

• Digital Modem (ISDN,DSL,Cable Modem)

A communications device that sends and receives data and information to and from a digital line.

• Wireless Modem

Some mobile users have a wireless modem that uses the cell phone network to connect to the Internet wirelessly from a notebook computer, a smart phone, or other mobile device.

Next Card

Sometimes called a network interface card, is a communications device that enables a computer or device that does not have built-in networking capability to access a network.

Wireless Access Point

A central communications device that allows computers and devices to transfer data wirelessly among themselves or to transfer data wirelessly to a wired network .

*Wireless access points have high-quality antennas for optimal signals.

Router

A communications device that connects multiple computers or other routers together and transmits data to its correct destination on a network.

Switch

A connection device similar to a hub but more sophisticated, including functionality that allows it to control and manage data transmissions.

Hub

A connection device that allows multiple connections to the network.

TYPES OF TRANSMISSION MEDIA

Transmission media is a pathway that carries the information from sender to receiver. We use different types of cables or waves to transmit data. Data is transmitted normally through electrical or electromagnetic signals.

An electrical signal is in the form of current. An electromagnetic signal is series of electromagnetic energy pulses at various frequencies. These signals can be transmitted through copper wires, optical fibers, atmosphere, water and vacuum Different Medias have different properties like bandwidth, delay, cost and ease of installation and maintenance. Transmission media is also called Communication channel.

(1) Wired or Guided Media or Bound Transmission Media : Bound transmission media are the cables that are tangible or have physical existence and are limited by the physical geography. Popular bound transmission media in use are twisted pair cable, co-axial cable and fiber optical cable. Each of them has its own characteristics like transmission speed, effect of noise, physical appearance, cost etc. 

Twisted Pair Cable

•Twisted-pair cable consists of one or more twisted-pair wires bundled together.

•Widely used transmission media for network cabling and telephone systems.

Coaxial Cable

Consists of a single copper wire surrounded by at least three layers: 

An insulating material

A woven or braided metal

A plastic outer coating .

Fiber Optic

A transmission media that uses glass or plastic fiber to carry light (laser) signals.

(2) Wireless or Unguided Media or Unbound Transmission Media : Unbound transmission media are the ways of transmitting data without using any cables. These media are not bounded by physical geography. This type of transmission is called Wireless communication. Nowadays wireless communication is becoming popular. Wireless LANs are being installed in office and college campuses. This transmission uses Microwave, Radio wave, Infra red are some of popular unbound transmission media.

Infrared 

Infrared (IR) is a wireless transmission medium that sends signals using infrared light waves.

Broadcast Radio (Bluetooth, Ultra Wideband (UWB), WiFi, WiMAX) 

A wireless transmission medium that distributes radio signals through the air over long distances such as between cities, regions, and countries and short distances such as within an office or home.

Cellular Radio (2G,3G,4G) 

A form of broadcast radio that is used widely for mobile communications, specifically wireless modems and cell phones

Microwave 

Microwaves are radio waves that provide a high-speed signal transmission.

* Microwave transmission, often called fixed wireless, involves sending signals from one microwave station to another.

Communications Satellite 

Is a space station that receives microwave signals from an earth-based station, amplifies (strengthens) the signals, and broadcasts the signals back over a wide area to any number of earth-based stations.