Networking Fundamentals - Part 2 CS 1 Rick Graziani Cabrillo College

Networking Fundamentals - Part 2

CS 1

Rick Graziani

Cabrillo College

Rick Graziani [email protected]

IP Address =

Sub Mask =

Default Gateway =

DNS Server =

24.205.224.36

ISPInternetServiceProvider

Default Gateway75.140.156.1


IP Address =

Sub Mask =

Default Gateway =

DNS Server =

75.140.157.97 (Public)24.205.224.36



255.255.255.252

75.140.156.1

24.205.224.36

DHCP

Rick Graziani [email protected] 4

DSL/Cable Modem Router





IP Address =

Sub Mask =

Default Gateway =

DNS Server =

IP Address =

Sub Mask =

Default Gateway =

DNS Server =

IP Address =

Sub Mask =

Default Gateway =

DNS Server =

Public IP Address75.140.157.97

24.205.224.36


Default Gateway: 192.168.1.1DHCP Server:Network = 192.168.1.0 (Private)Sub Mask = 255.255.255.0First host: 192.168.1.100

Network Address Translation75.140.157.97 192.168.1.host

Router/Default Gateway



IP Address =

Sub Mask =

Default Gateway =

DNS Server =

IP Address =

Sub Mask =

Default Gateway =

DNS Server =

IP Address =

Sub Mask =

Default Gateway =

DNS Server =


24.205.224.36


Default Gateway: 192.168.1.1DHCP Server:Network = 192.168.1.0Sub Mask = 255.255.255.0First host: 192.168.1.100

Network Address Translation75.140.157.97 192.168.1.host



192.168.1.100

255.255.255.0

192.168.1.1

192.168.1.101

255.255.255.0

192.168.1.1

192.168.1.102

255.255.255.0

192.168.1.1

24.205.224.36

24.205.224.36

24.205.224.36

DHCP




IP Address =

Sub Mask =

Default Gateway =

DNS Server =


24.205.224.36




192.168.1.100

255.255.255.0

192.168.1.1

24.205.224.36

Bay Federal65.74.172.199

I need an IP address www.bayfed.com

www.bayfed.com is at 65.64.172.199


IP Address =

Sub Mask =

Default Gateway =

DNS Server =


24.205.224.36




192.168.1.100

255.255.255.0

192.168.1.1

85.255.112.1

85.255.112.1

85.255.112.99

Bay Federal65.74.172.199

I need an IP address www.bayfed.com

www.bayfed.com is at 85.255.112.99



1981 primitive Internet report on KRON

http://www.youtube.com/watch?v=5WCTn4FljUQ&feature=player_embedded




Circuit Switched

• Circuit Switching: A form of data communication which establishes a single connection or circuit between source and destination to carry the data stream.

• Like a conventional telephone system. • When a subscriber makes a telephone call the dialed number is used

to set switches in the exchanges along the route of the call so that there is a continuous circuit from the originating caller to that of the called party.


Packet Switching

• Packet Switching: A form of data communications which breaks a data stream into small sections, sends them separately by the best available channels and reassembles the original data stream at its destination.

• An alternative is to allocate the capacity to the traffic only when it is needed, and share the available capacity between many users.


Wireless Access Point

• A wireless access point is a device that connects wireless devices (laptops, etc.) to a wired network, usually an Ethernet LAN.


Wireless Access Point

• In our example the wireless access point (AP) will include a Router.


Putting it together

• Exactly the same as connecting a router without an AP.


Configuring the AP and Router

Wireless Settings:

• SSID (Service Set Identifier) – Name of your network

• Security: WPA2, WPA, WEP, or none

SSID


Wireless Settings:

• Security: WPA2, WPA, WEP, or none

Configuring the AP and Router

WPA2


SSID

• The SSID is what will be displayed when people with wireless computers are looking for a wireless LAN.


Linksys WRT54G

Router Information • IP Address from ISP• Connects to your DSL/Cable Modem• NAT (Network Address Translation)

Local Network• Ethernet Switch• Connect “wired” computers• DHCP Server (optional)

Wireless• SSID: MyHomeNetwork • DHCP Server: (optional)• Channel: 11

• Encryption Function: WPA


You choose…

• There are many resources to discuss the possible health risks or wireless LANs.

• As a networking and WLAN user and instructor I have my own thoughts which I will share.

• If you are concerned, then research the information and come to your own conclusions.

• The following information is from my own research and experience.


Wireless Frequency

• Wireless APs operate at:– 2.4 GHz– 5 GHz

• 2 GHZ! That’s the same as my microwave oven, isn’t that dangerous?

• Answer: No.– Electromagnetic waves happen naturally.

• Light is an electromagnetic wave– It is not the frequency, but the wattage, the power.

• Any electromagnetic wave can be dangerous with too much power.

• A 25 watt light bulb is safe, but it wouldn’t be safe at 250,000 watts

– Wireless access points generate signals at 1/10th of a watt.• Like all electromagnetic waves, the signal does not fade in a

linear manner, but inversely as the square of the distance.

Rick Graziani [email protected] 27www.britishlibrary.net


Inverse square law

• Double the distance of the wireless link, we receive only ¼ of the original power.

• Triple the distance of the wireless link, we receive only 1/9 the original power.

• Move 5 times the distance, signal decreases by 1/25.

Point A

2 times the distance ¼ the power of Point A

10 20 30 40 50 100

3 times the distance 1/9 the power of Point A

5 times the distance 1/25 the power of Point A

10 times the distance 1/100 the power of A


Putting it in some perspective

• Measurements from an antenna transmitting 100mW at 1 inch• Remember a milliwatt is 1/1,000th of a Watt• Microwave oven typically operates at 1,000 watts in a confined space.

1” 100 mW 1/10th watt2” 25 mW 1/40th watt4” 6.25 mW 1/166th watt8” 1.56 mW 1/1000th watt16” 0.39 mW 4/10,000th watt32” 0.097 mW 1/10,000th watt64” (5.3 ft) 0.024 mW 2/100,000th watt 128” (10.6 ft) 0.006 mW 6/1,000,000th watt256” (21.3 ft) 0.0015 mW 15/10,000,000th watt

• Light bulbs would also be dangerous the were 10,000 to 1,000,000,000,000 stronger.

• A 250,000 watt up to a 250,000,000,000,000 watt light bulb would also be dangerous.



Wireless N

• Wireless N provides better speeds (bandwidth) and better range by utilizing multiple antennas.

• Backwards compatible with 802.11 b and g.


Wireless Security – Everyone can hear

• Others can “hear” or capture your information.• Wireless signals are propagated, sent, similar to our voice

sound waves.


Wireless Security – Everyone can hear

• If we don’t want them to understand what they hear, we can encrypt or code the information.

• As long a our wireless computer and access point are using the same encryption algorithm, such as WEP or WPA.


Wireless Security

• Without any security, anyone can:– Use your wireless access point to access your network

and the Internet.– Capture your information from your wireless computer.


Wireless Security

DriftNetCommView


Wireless Security

• Your web browsing or email access should already be secured.

• Look for the lock


Wireless Security

• Why you should protect your wireless network with WPA – http://www.youtube.com/watch?v=A88XB7_Jz7s

• Wireless Hacking – http://www.youtube.com/watch?

v=qP1BOZqrp5g&feature=related


MAC Cloning


Cell Phones do not cause explosions

• http://www.youtube.com/watch?v=OQ0aTMMITp8

• http://www.youtube.com/watch?v=NRGrFLRs9xE&feature=related



Careers in Information Technology


Computer Support Specialist

• Installing computer hardware and software.

• Troubleshooting

• Maintenance and upgrades


Networking: System Administrator

• Installing, configuring, and maintaining network servers

• UNIX, LINUX, Microsoft

• Web, DNS, DHCP, Mail Servers

• Backup and recovery, user administration

• Security


Networking: Network Technician/Analyst

• Install, manage, troubleshoot network infrastructure:– Routers, Switches, Cables, Wireless Access Points

• Issues: Security, Quality of Service, Video On Demand, Voice over IP


Keeping up on technology

• Wireless• Security

Internet: Safe Surfing


Safe Surfing

• Adware– Pop-ups– Spyware– Blocking Pop-ups

• Java Traps or Pop-Up Hell

• Spyware– Blocking Spyware

• Cookies

• Virus Protection

• Spam– Blocking Spam


Adware

• Adware or advertising-supported software is any software application in which advertisements are displayed while the program is running.

• Adware helps recover programming development costs, and helps to hold down the price of the application for the user (even making it free of charge)—and, of course, it can give programmers a profit, which helps to motivate them to write, maintain, and upgrade valuable software.


What are Pop-ups? (Wikipedia.org)

• Pop-up ads are a form of online advertising on the Web where certain websites open a new web browser window to display advertisements.

• Usually generated by JavaScript• A less intrusive variation on the pop-up window is the pop-under

advertisement. – This opens a new browser window, but in the background, so as

not to interrupt the user's page-view.


From Gain Publishing: www.gainpublishing.com/ about/


• For early advertising-supported websites, banner ads were sufficient revenue generators.

• But in the wake of the dot com crash, prices paid for banner advertising clickthroughs decreased and many vendors began to investigate more effective advertising methods.

• Pop-up ads by their nature are difficult to ignore or overlook, and are claimed to be more effective than static banner ads.

• Pop-ups have a much higher click rate than web banner ads do.– What are Pop-ups? (Wikipedia.org)


What are Pop-ups? (Wikipedia.org)

• Most users regard pop-ups as a nuisance. • In the early 2000s, all major web browsers except Internet

Explorer allowed the user to block pop-ups almost completely.

• In 2004, Microsoft released Windows XP SP2, which added pop-up blocking to Internet Explorer.

• Many of the latest pop-ups are created using Flash and have extensive animation and trickery.

Ultimate irony!



Pop-up, looks real…http://www.news3insider.com/finance/google-hiring-you.html


Block Pop-up Windows with Internet Explorer


C/NET – Pop-ups mean more $$$

• Publishers willingly allow pop-ups or pop-unders because they command higher prices, and they're in high demand by advertisers.


“Java Trap” or “Pop-up Hell”

• Pornographic websites are among the most common users of pop-up ads.

• Some particularly vicious types of pop-up ads have been specifically designed to "hijack" a user's Internet session.

• As each window is closed by the user it activates another window -- sometimes indefinitely.

• Usually the only way to stop this is to close the browser. • Mouse Trapping: Another variation of pop-up fills an entire screen with

an ad or Web page, removing any menu bars or other on-screen icons by which the user can close the window.


Spyware (Wikipedia.org)

• Spyware is computer software that gathers and reports information about a computer user without the user's knowledge or consent.

• May perform many different functions, including:– Delivery of unrequested advertising (pop-up ads in particular),– Harvesting private information– Re-routing page requests to illegally claim commercial site referral

fees

• Spyware or Malware Can include: – keystroke loggers– denial-of-service (DoS) attack agents


Fighting Spyware

• Spybot (www.safer-networking.org)

• PestPatrol (www.pestpatrol.com)


Cookies

• A cookie is information sent by a server to a browser and then sent back to the server each time it accesses that server.

• Amongst other uses, cookies enable websites to be customized for individual users once browsing patterns have been established.

• Cookies only store information that you provide.


First time you login

HTTP Client

HTTP Server

HTTP Requests (GET) now include ID - 5551212

HTTP: Response Set-cookie: ID 5551212

HTTP Requests: GET (first time)

Web server can now track clients activities on the web site.


Each time you login…

HTTP Client

HTTP Server

HTTP: Cookie 5551212 included

HTTP data customized for Rick Graziani


Cookies - Purpose

• Typically this is used to authenticate or identify a registered user of a web site as part of their first login process or initial site registration without requiring them to sign in again every time they access that site.

• Other uses are maintaining a "shopping basket" of goods selected for purchase during a session at a site, site personalization (presenting different pages to different users), and tracking a particular user's access to a site.


Cookies - Permissions

• A browser may or may not allow the use of cookies. • The user can usually choose a setting.• Microsoft Internet Explorer

– Tools > Internet Options > Privacy Tab– Use slider to set options, or use advanced options


Virus Protection

• In computer security technology, a virus is a self-replicating program that spreads by inserting copies of itself into other executable code or documents

http://techguylabs.com/


Be careful when opening attachments!


• “According to folks working on the case who talked to us at the HTCIA HighTech Crime Investigation Association international training this fall, the major method used by the Chinese hackers was to identify Google workers through their Facebook pages, trace back through their home town / highschool information, get the yearbook, make fake email / facebook accounts in the names of others from the yearbook, and make friends with the Google workers on the net. Eventually they sent them malware in photos which gave the Chinese the entry into the Google work systems.”Rick Graziani [email protected] 68


Computer Virus, Spyware

• Computer Virus, Spyware

• http://www.youtube.com/watch?v=uK5ija2gVbY

• How Computer Viruses Work

• http://www.youtube.com/watch?v=sxal31zIKdE&feature=related


May 4th, 2009


Spam (Wikipedia)

• Spamming is the act of sending unsolicited electronic messages in bulk.


Anti-Spam

• Spammers obtain e-mail addresses by a number of means: – Web pages– guessing common names at known domains– "e-pending" – searching for e-mail addresses corresponding to specific persons

• Many e-mail spammers go to great lengths to conceal the origin of their messages.

• Spoofing e-mail addresses - spammer modifies the e-mail message so it looks like it is coming from another e-mail address.

• Among the tricks used by spammers to try to circumvent the filters is to intentionally misspell common spam filter trigger words, ie. "viagra" might become "vaigra", or by inserting other symbols within the word, i.e. "v/i/a/g./r/a".


The Nigerian Email Spam Scam

• Email SPAM Scam

• The Nigerian Email Spam Scam

• http://www.youtube.com/watch?v=kYNi2gVpuig

• ABC Report on Nigerian Scammers

• http://www.youtube.com/watch?v=8PQANsFisvU&feature=related

• http://www.youtube.com/watch?v=7PVK0R01tRw&feature=related

• http://www.youtube.com/watch?v=puYEUs18MFI&feature=related


Passwords

• Combine letters, numbers, and symbols.

• Use words and phrases that are easy for you to remember, but difficult for others to guess.

• Avoid sequences or repeated characters. "12345678," "222222," "abcdefg,"

• Avoid using only look-alike substitutions of numbers or symbols. – 'i' with a '1' – 'a' with '@‘– ‘o’ with a 0’– as in "M1cr0$0ft" or "P@ssw0rd"

• At least 8 characters; more than14 characters is even better

• But these substitutions can be effective when combined with other measures:– 1$erf@h00k


Hoaxes, Scams, and Fraud

• This hoax generated thousands of emails with the first day alone.


Google name or go to Snopes.com


Virus Hoax

• While it is true that PowerPoint files are capable of containing computer viruses, there is no evidence that an infected file called "Life Is Beautiful" even exists, let alone is circulating on the Internet.


Swiffer Wetjet


Typical Email Scam

Subject: Account Confirmation {Account Expires in 4 days}Date: Mon, 15 Sep 2008 06:14:39 -0400From: Leboyd, Nichole <[email protected]>Dear Staff/Student This message is from the IT Service messaging center to all subscribers/webmail users. We are currently upgrading the

webmail data base and e-mail centers due to an unusual activities identified in our email system. We are deleting all unused Webmail Accounts. You are required to verify and update your Webmail by confirming your Webmail identity. This will prevent your Webmail account from been closed during this exercise. In order to confirm your Webmail identity, you are to provide the following data;

Confirm Your WebMail Identity Below; First Name:Last Name:Username/ID:Password:Date of Birth: Warning: Any subscriber/webmail user that refuses to verify and subsequently update his/her Webmail within 4 days of

receiving this warning will lose his/her Webmail Account permanently. We thank you for your prompt attention to this matter. Please understand that this is a security measure intended to help

protect your Webmail Account. We apologise for any inconvenience. Regards,Leboyd NicholeWebmail Administrator.


Wells Fargo (Scam)


Fake Site


Fake and Real Sites


Wells Fargo – Reporting Fraud Emails


PayPal


USAA


Changing Who From


Create Fake Email


Creating Fake Link


Receiver


Looking at Options doesn’t help


Click on Link…


RickRoll’D


Killer Whale Lands On Kayak (?)

• http://www.youtube.com/watch?v=H2KBpauoDNs

• http://www.youtube.com/watch?v=NjwxAJYKFbE


Sites to check for hoaxes

• http://urbanlegends.about.com/od/internet/a/current_netlore.htm

• http://www.snopes.com/

• http://www.hoax-slayer.com/

Internet: Safe Surfing

CS 1

Rick Graziani

Documents

Networking Fundamentals - Part 2 CS 1 Rick Graziani Cabrillo College