About Network

8/12/2019 About Network

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MBE 13203Information Technology in TVET

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Networking and Security:

Connecting Computers and Keeping

Them Safe from Hackers and Viruses

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Chapter Topics (part 1)

Networking fundamentals Network architecture Network components

Peer-to-peer networks Ethernet networks Power-line networks Configuring software

Wireless security


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Chapter Topics (part 2)

Computer virus types

Protecting computers from viruses

Hackers

Firewalls Passwords and password management

Biometrics

Spyware and spam Backup methods

Protecting physical assets


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Networking Fundamentals

Computer network

Two or more computers connected together

Devices connected to networks: nodes

Benefits of a network Sharing resources and peripherals

Transferring files

Sharing of broadband connection with use of a

router


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Network Architecture

Network designs

Locally administered

Peer-to-peer (P2P)

Centrally administered Client/server


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Peer-to-Peer Networks

Nodes communicate with each other

Peers

Share peripheral devices

Common in home networks


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Client/Server Networks

Client computers

Users who make requests

Server computers

Provide resources to clients Central network control

Internet

A large, multiserver,

multiclient network


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HANs and LANs

Home area network (HAN)

Connects digital devices within a home

Local area network (LAN)

Nodes are within a small geographic region Schools

Small businesses


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WANs and MANs

Wide area network (WAN)

LANs connected over long distances

A few miles to thousands of miles

Uses telecommunications lines Metropolitan area network (MAN)

Provides access within a specific geographicregion, such as a city


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Network Components

Transmission media Network communication

devices

Software


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Transmission Media

Provide communications channel between nodes Forms of media

Twisted pair cable Coaxial cable

Fiber-optic cable Radio waves (wireless) Bandwidth

Data transfer rate Throughput


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Network Adapters

Devices connected to or installed in nodes

Network interface cards (NICs)

External or internal network adapters

Enable communication between nodes


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Network Navigation Devices

Devices that help make data flow possible

Routers

Route data between networks

Switches Receive data and retransmit it to nodes on the

same network


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Networking Software

Peer-to-peer software Built into operating systems that support

networking

Windows

Mac OS

Linux

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Networking Software

Client/server software Network operating system (NOS) software

Windows Server 2008

SUSE Linux Enterprise

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Types of Peer-to-Peer Networks

Wired Ethernet networks

Wireless Ethernet networks

Power-line networks

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Wired Ethernet Networks

Ethernet networkadapters are used toconnect nodes

NIC card ExpressCard USB adapter

Computers are connected

to each other usingunshielded twisted paircable

Ethernet Phone

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Ethernet Switches

Keep track of data packets

Amplify and retransmit signals

Keep the network running efficiently

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Ethernet Routers

Transfer packets from onenetwork to another

Home Internet routers

transfer data from theInternet to the homenetwork

Allows for network-ready

devices such as networkprinters or networkattached storage (NAS)


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Wireless Ethernet Networks

Ethernet networks that use radio waves instead ofwires to connect nodes

Based on the IEEE 802.11 standard, also known

as Wi-Fi Each node requires a wireless network adapter

Transceivers

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Wireless Access Point (WAP)

Device added to a wireless network to extend therange of the network

Must connect to either a switch, a router, or a

node on the network

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Power-Line Networks

Computers areconnected to ahouses electricalwiring to create anetwork

A power-line networkadapter connectsnodes to electrical

outlets

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Choosing a Peer-to-Peer Network

Things to consider- Whether existing wiring is available- Whether you want wireless communications

- How fast you want your network connection to be

- How much money you can spend on your network

Comparing the Major Types of Home Networks

WiredEthernet

Power-Line

Wireless802.11g

Wireless802.11n

Maximum data transfer rate(bandwidth)

100 Mbps to1 Gbps

200 Mbps 54 Mbps 540 Mbps

Relative installation andequipment costs fornetworkingtwo computers

$ $$ $ $$

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Configuring Software

for Your Home Network

Windows Vista and later versions

Use wizards launched from Network and SharingCenter in Control Panel

Before running wizards:1. Install network adapters on each node.

2. For a wired network, plug all the cables into therouter, network adapters, and so on.

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Configuring Software

for Your Home Network

3. Make sure your cable/DSL modem is connected toyour router and the Internet.

4. Turn on your equipment in the following order:

a. Cable/DSL modemb. Router

c. All computers and peripherals (printers,

scanners, and so on)

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Networking Multiple Versions

of Windows

Set up Windows 7 and Vista machines first

Automatically detect other computers runningWindows on network

Windows XP will need adjustment to see otherversions of Windows

Give each Windows computer a unique name

Place all computers in the same workgroup

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Configuring a Router to

Connect to the Internet

Contact ISP for special settings

Access router from Web browser

Enter username and password

Use routers wizard to set up connection usingsettings and info provided by ISP

Test Internet connection speed

Speedtest.net

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Securing Wireless Networks

Wireless network range doesnt stop at theproperty line

Default device and network ID settings allow

intruders to enter the network Internet bandwidth can be stolen

Computers can be vulnerable to hacker intrusionand takeover

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Securing Wireless Networks

To secure a wireless network, do the following:

Change your network name (SSID)

Disable SSID broadcast

Change the default password on your router Turn on security protocols

Implement media access control

Limit your signal range

Apply firmware upgrades

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Chapter 7 Summary Questions

What is a network, and what are the advantagesof setting one up?

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What is the difference between a client/servernetwork and a peer-to-peer network?

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What are the main hardware components ofevery network?

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What are the most common home networks?

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What are wired Ethernet networks, and how arethey created?

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What are wireless Ethernet networks, and howare they created?

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How are power-line networks created, and arethey a viable alternative to Ethernet networks?

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How do I configure my computers software toset up a network?

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Why are wireless networks more vulnerable thanwired networks, and what special precautionsare required to ensure my wireless network is

secure?

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PART 2

3/6/2014


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Computer Threats

Cybercrimes are criminal acts conducted bycybercriminals through the use of

computers Computer users need to protect themselves

from becoming victims of cybercriminals


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Types of Cybercrime

Fraud-related (58 percent of cybercrime) Auction fraud

Nondelivery of ordered items

Credit and debit card fraud

Non-fraud-related

Computer intrusions

Unsolicited e-mail

Child pornography


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Computer Threats: Viruses

Virus: A program that attaches itself to anotherprogram and spreads itself to other computers

Viruses are hidden within the code of a host

program


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What Viruses Do

Replicate themselves Slow down networks

Secondary objectives

Display annoying messages Delete files on the hard drive

Change computer settings


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How Does a Computer

Catch a Virus? Viruses copy

themselves andinfect a file onyour computer

Spread by Sharing disks or

flash drives Opening an e-mail

attachment Downloading

infected audio orvideo files


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Types of Viruses

Boot-sector viruses Replicate themselves in the boot sector of the hard

drive Logic bombs

Activate when certain conditions are met Time bombs Triggered by the passage of time or on a certain

date Worms

Travel between systems through networks


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Types of Viruses

Script viruses Hidden on Web pages as miniprograms

Macro viruses Attached to documents

E-mail viruses Use e-mail address books to distribute themselves Encryption viruses

Compress files using a complex encryption key


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Virus Classifications

Polymorphic viruses

Periodically rewrite themselves to avoid detection

Multipartite viruses

Infect multiple file types Stealth viruses

Erase their code from the hard drive and reside inthe active memory


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Antivirus Software

Programs designed todetect viruses Scan files looking for

virus signatures (uniquecode)

Provide options fordeleting or fixinginfected files

Inoculate files against

further infection Needs to be updated

frequently


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Dealing with an

Infected Computer

1. Boot computer with antivirus DVD/CD in DVDdrive.

2. Run directly from DVD/CD.

3. Allow software to delete or quarantine infectedfiles.

4. Research viruses found to ensure furthermanual steps are not needed.


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Prevent Instant

Messaging Viruses

Allow contact from Buddy or Friends List usersonly.

Never automatically accept transfers of data.

Avoid using instant messaging programs onpublic computers.


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Other Ways to Protect

Your System

Keep your antivirus and operating system (OS)software up to date

Load security patches as soon as they are

available Enable automatic updates

H k


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Hackers

Anyone who unlawfully accesses a computersystem

Types of hackers

White hat

Black hat Script kiddies


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What Hackers Steal

Hackers try to steal data stored on hard drives:

Credit card numbers

Bank account numbers

Also can steal information through packetsniffing

Use information to commit identity theft


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How Computers Are Attacked

Trojan horse

Backdoor program

Zombies

Denial of serviceattacks (DoS)

Distributed denial ofservice attacks

(DDoS)


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How Hackers Gain Access

Direct access

Hacking software

Indirect access

Internet connection Logical ports


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Firewalls

Software programs or hardware designed to closelogical ports to invaders

A software firewall is built into Windows 7

Other software firewalls are available from vendors

Network routers can contain a hardware firewall Firewalls are critical if you have an always-

on broadband connection

Test your computers vulnerability


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Bluetooth Attacks

Bluesnarfing

Exploits flaw in access software to stealinformation contained on the device

Bluebugging Hacker takes control of the device

Make your device invisible


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Wireless Networks on the Road

Beware

Evil twins

Free Internet access in paid locations

Protect yourself Check with authorized personnel for official name

of hot spot

Do not use free access from unknown sources


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Passwords

Create a strong password At least 14 characters, including numbers,

symbols, and upper- and lowercase letters

Not a single word or a word from a dictionary

Not easily associated with you (birthday, name ofpet, nickname)

Use different passwords for different sites

Do not tell anyone or write down password

Change password regularly (every month)


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Password Managers

Remember all your different passwords Built into

Operating systems

Web browsers

Some securitypackages


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Anonymous Web Surfing

Public computers Shared computers risk subsequent user viewing

your data

Might already have viruses or hacking toolsinstalled

Portable privacy devices

Linux OS on a flash drive


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Biometric Authentication Devices

Read unique personal characteristics Fingerprint Iris patterns Voice patterns

Face patterns


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Malware

Software that has a malicious intent Grayware (nondestructive)

Adware

Spyware

Viruses (destructive)


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SPAM or SPIM

SPAM: Unwanted or junk e-mail To avoid SPAM

Create free Web-based e-mail account for filling outonline forms or making online purchases

Use a spam filter

Do not try to unsubscribe from spam e-mails

Use an e-mail forwarding service

SPIM: Unsolicited instant messages


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Cookies

A Web site assigns an ID number to yourcomputer, stored in a cookie file

Each time you log in to the site, it notes the visit

and keeps track of it in a database Provide info about browsing habits

Identify user preferences

Pose some privacy risks, but low security threat


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Backing Up Your Data

Backup A copy of a file that can be used to replace the

original

Types of files to back up Program

Data

Backup routine

Frequency Changed files


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Software programs for easy backup Schedule automatic backups

Can back up files, folders, or entire drives

Back up to USB device, CD, or DVD Entire system backup software

Takes an image of the entire system

Stores on a separate hard drive

In case of failure, a new drive is inserted


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Store backups offsite

Online backups

Store backup files on Internet servers

Fees for the service


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Social Engineering

Uses social skills to generate human interactionto entice individuals to reveal sensitiveinformation

Usually does not use a computer or face-to-faceinteraction

Pretexting


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Phishing and Pharming

Phishing Uses e-mail to lure user to fake Web sites

Tricks user into revealing private data

Pharming Malicious code changes Web browsers ability tofind Web addresses


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Hoaxes

An attempt to makesomeone believesomething that isuntrue

Target large audiences Practical joke, agents of

social change, or timewasters

Mostly e-mail


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Protect Physical Assets

Environmental factors Avoid

Sudden movement

Excessive heat or cold

Dust

Food and liquids

Use padded case for notebooks


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Power Surges

Occur when electrical current is supplied inexcess of normal voltage (120 volts in the UnitedStates)

Caused by: Old or faulty wiring

Downed power lines

Malfunctions at electric substations

Lightning strikes Use surge protectors


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From which types of viruses do I need to protectmy computer?


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What can I do to protect my computer fromviruses?


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How can hackers attack my computing devices,and what harm can they cause?


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What is a firewall, and how does it keep mycomputer safe from hackers?


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How do I create secure passwords and manageall of my passwords?


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How can I surf the Internet anonymously anduse biometric authentication devices to protectmy data?


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How do I manage online annoyances such asspyware and spam?


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What data do I need to back up, and what arethe best methods for doing so?


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What is social engineering, and how do I avoidfalling prey to phishing and hoaxes?


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How do I protect my physical computing assetsfrom environmental hazards, power surges, andtheft?

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