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CS 312 Internet Concepts

Internet Applications

Dr. Michele Weigle Department of Computer Science

Old Dominion University [email protected]

http://www.cs.odu.edu/~mweigle/CS312-F11/

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Three Questions

! What is the Internet?

! Who uses the Internet?

! What applications run over the Internet?

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What is the Internet? Shai Carmi, Shlomo Havlin, Scott Kirkpatrick, Yuval Shavitt, and Eran Shir. "A model of Internet topology using k-shell decomposition". Proc. Natl. Acad. Sci. USA 104, 11150 (2007).

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Who uses the Internet?

http://weblogs.mozillazine.org/gerv/archives/2007/images/internet_dog.jpg

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What applications run over the Internet?

http://nmap.org/favicon/

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! Email »  free email, spam,

phishing, mailing lists, netiquette

!  Instant messaging ! Social networking

»  Facebook, MySpace

! Blogs ! Wikis

! Streaming media »  YouTube, Hulu

!  Internet telephony »  Skype

! Google Documents

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Email

! Send messages (text, images, video) to other users »  not real-time

! Messages are processed through mail servers and stored in mailboxes »  like the post office

! We'll get into more detail about how it actually works when we talk about SMTP (Simple Mail Transfer Protocol)

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Email Free Email – Yahoo!

! mail.yahoo.com ! unlimited storage

!  integrated chat !  image-based ads

260+ million users

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Email Free Email – Gmail (Google)

! gmail.com ! 7 GB storage

»  can purchase more

!  integrated chat !  text-based ads ! good spam filters

tens of millions of users

http://www.youtube.com/watch?v=8FVme_xIRYk

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Email “Other” Uses of Email

! Spamming »  Sending unsolicited messages in bulk

" mostly for advertising

! Phishing – attempting to fraudulently acquire sensitive information through email »  “Nigerian Sting” – fraudulently requesting money »  manipulating stock prices »  sending viruses or other malicious programs

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“Other” Uses of Email Nigerian Scam

LAGOS, NIGERIA.

ATTENTION: THE PRESIDENT/CEO

DEAR SIR,

CONFIDENTIAL BUSINESS PROPOSAL

HAVING CONSULTED WITH MY COLLEAGUES AND BASED ON THE INFORMATION GATHERED FROM THE NIGERIAN CHAMBERS OF COMMERCE AND INDUSTRY, I HAVE THE PRIVILEGE TO REQUEST FOR YOUR ASSISTANCE TO TRANSFER THE SUM OF $47,500,000.00 (FORTY SEVEN MILLION, FIVE HUNDRED THOUSAND UNITED STATES DOLLARS) INTO YOUR ACCOUNTS. THE ABOVE SUM RESULTED FROM AN OVER-INVOICED CONTRACT, EXECUTED COMMISSIONED AND PAID FOR ABOUT FIVE YEARS (5) AGO BY A FOREIGN CONTRACTOR. THIS ACTION WAS HOWEVER INTENTIONAL AND SINCE THEN THE FUND HAS BEEN IN A SUSPENSE ACCOUNT AT THE CENTRAL BANK OF NIGERIA APEX BANK.

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“Other” Uses of Email Nigerian Scam

In a 1997 newspaper article:

“We have confirmed losses just in the US of over $100 million in the last 15 months,” said Special Agent James Caldwell, of the Secret Service financial crimes division. “And that’s just the ones we know of. We figure a lot of people don’t report them.”

http://www.snopes.com/crime/fraud/nigeria.asp

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“Other” Uses of Email Phishing

!  Send thousands or even millions of emails !  Links or buttons take readers to fraudulent websites

»  don’t follow links directly (view source if you’re suspicious) »  <a href=“www.myphishingsite.com”>Bank of America</a>

!  Fraudulent sites mimic well known sites, collecting personal information

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“Other” Uses of Email How to Avoid Spam

! Legislative attempts »  fine spammers

! Avoid giving away your email address ! Don’t publicize your email address on web pages

»  use username at cs dot odu dot edu »  use image that shows your email address

! Use e-mail client’s spam filtering features ! Reporting to the e-mailer’s ISP

»  usually doesn’t work because from address is often spoofed

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“Other” Uses of Email Computer virus, worm, and Trojan horse

!  Computer virus »  a self-replicating

program »  spreads by inserting

copies of itself into other executable code or documents

!  Computer worm »  a self-replicating

program »  self-contained, does not

need to be part of another program to propagate itself

! Trojan horse »  a malicious program

disguised as a useful software

»  may be deliberately attached to an otherwise useful software

»  may spy on user actions

»  does not replicate itself »  may spread virus

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“Other” Uses of Email Avoiding Viruses and Attacks

! Recognize virus tricks »  Mostly from attachments

" Executable files: .exe, .vbs, .com, .scr, .pif, etc. " Zipped files " Disguised file names: appearing to be .txt, .jpg but appended

with many blanks then the real extension name

»  Often with attractive/sympathy subject line or content " Money making opportunities " Free offers " Friendly warnings " Pleas for assistance

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“Other” Uses of Email Avoiding Annoying Emails

!  Hoaxes and chain letters »  Hoaxes are false claims. »  Purpose: to be sent to everyone you know, to make mail

servers slow down to a crawl »  False charitable solicitations »  Chain letters often offer luck or money »  False warnings »  False offers

!  Verifying possible hoaxes »  www.snopes.com »  www.hoax-slayer.com »  www.truthorfiction.com

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Email Mailing Lists

!  A collection of names and email addresses !  distribution list

»  maintained by your email client »  to or cc or bcc (blind carbon copy) line contains each email

address »  to send email to everyone on the list, must include everyone's

email address in the to, cc, or bcc line !  electronic mailing list

»  maintained by mailing list software (ex: listserv, mailman) »  to line contains just the email address of the list itself

"  individual email addresses are not shown »  to send email to everyone on the list, just send to the list address »  http://occs.odu.edu/accounts/mailinglist/index.shtml »  http://list.odu.edu/mailman/listinfo/cs795-mcw

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Email Netiquette

! The conventions of politeness recognized in email

! Basic Rules »  Think before you click “Send” »  Use a subject line that describes what the message is

actually about »  Re-read and edit your message

" use a spell checker

»  Be concise and to the point »  Use short paragraphs and leave a blank line between

them

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Email Netiquette – more basic rules

! When asking a question, do enough homework, and give details

! Avoid text chat lingo, especially when not emailing friends (i.e., don’t use this when emailing professors!)

!  In general, give your give full name and return e-mail address as your signature

! Avoid attachments if not appropriate

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Email Netiquette – more basic rules

! Reply only to those you need to »  don't always reply to all

! Remember that emails are not private

!  If you're on an electronic mailing list, there are usually instructions on how to unsubscribe yourself »  don't bug everyone else on the list by sending out

“Remove me from this list!” emails.

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Email Emailing Professors

To: [email protected] From: [email protected] Subject: Hey

can u tell me how to do number 4 on the problem set. i no u went over it in class but i have had a VERY LONG week lol tests ha ha ha and i lost my notes. pleeease help Stu

Tips on how to appropriately email a professor: http://mleddy.blogspot.com/2005/01/how-to-e-mail-professor.html

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Email Emailing Professors – general guidelines

!  Write a clear subject line that actually summarizes what the question is and what it might be connected to in the course

!  Address the professor in the email, and remember to use “Dr.” or “Prof.”

!  Give the professor some context for the question, including the particular assignment or activity you're working on.

!  Punctuate. Capitalize appropriately. Use complete words and sentences; this is not texting. Check your spelling.

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Email Emailing Professors – general guidelines

! Be specific and detailed about what the difficulty or challenge is regarding.

! Ask an actual question, rather than leaving it up to the professor to infer what you don't understand.

! Be nice and thank the professor for answering.

! Sign your full name and give whatever institutional markings might be helpful for the professor to keep this in context.

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! Blogs ! Wikis




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Instant Messaging

!  Allows you to communicate with others interactively over the Internet

!  Examples: AOL Instant Messenger (AIM), Google Chat, Yahoo! Chat »  example client software: Pidgin

!  Maintain groups of contacts

!  Set status and away messages

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Social Networking

! Connect with friends, join groups, post public messages, post videos, let friends know what you're doing through your status updates

! Examples »  MySpace »  Facebook »  Orkut »  Friendster

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Social Networking More Popular than Email!

http://www.businessinsider.com/chart-of-the-day-social-networking-vs-email-usage-2010-4

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Social Networking A Warning

!  It is becoming more common for employers and universities to search for applicants on social networking sites.

!  People have been fired or turned down for jobs or admission because of the content of their MySpace or Facebook pages.

!  Either do not put questionable content on your pages or do not allow anyone other than your friends to view your page. »  safer to avoid questionable content altogether

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Web Log, or Blog

! A website in which journal entries, or blog posts, are posted on a regular basis »  typically created and maintained by a single author »  displayed in reverse chronological order »  focuses on a particular area of interest »  may allow readers to contribute via comments

! Often located at web hosting services or specialized blog hosting services »  blogger.com, wordpress.com, tumblr.com

! “Blogs in Plain English” video »  http://www.youtube.com/watch?v=NN2I1pWXjXI

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Keeping Up With Blogs

! Technorati (www.technorati.com) »  blog aggregator

! RSS Feeds »  subscribe to a blog using RSS »  use software (like Google Reader) to read

" http://www.google.com/reader " notified when particular blogs are updated

»  “RSS in Plain English” video " http://www.youtube.com/watch?v=0klgLsSxGsU

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Subscribing to Blogs Firefox

Safari

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! Blogs ! Wikis




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Wiki

!  Database for allowing shared access »  shared ownership of the collected work

!  Usually has many authors !  Structure determined by content and users !  Contains both internal links (to other pages in the wiki)

and external links !  Also commonly used to create websites quickly and easily

(even if only one author)

!  Examples »  http://en.wikipedia.org/wiki/Wiki »  http://www.emacswiki.org/cgi-bin/wiki

!  “Wikis in Plain English” Video »  http://www.youtube.com/watch?v=-dnL00TdmLY

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Streaming Media

! Allows the user to start playing a multimedia file (audio or video) before the entire file has downloaded

! Before streaming media became popular, you had to download the entire file before you could start playing it »  this could take a long time, so it wasn’t convenient for

web applications

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Streaming Media On the Web

!  YouTube http://www.youtube.com »  User-generated content »  Some copyrighted content, but it often disappears when the

copyright holder finds out about it »  Bought by Google in 2006

!  Hulu http://www.hulu.com »  Free service offering TV shows and movies from NBC, Fox,

and others »  http://www.hulu.com/watch/14394/hulu-walkthrough-

hulucom-walkthrough

!  TV Network Websites »  Many offer free viewing of full episodes of selected shows

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Streaming Media On the Web - YouTube

http://youtube.com/watch?v=5P6UU6m3cqk

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Streaming Media On the Web - Hulu

http://www.hulu.com/watch/14394/hulu-walkthrough-hulucom-walkthrough

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! Blogs ! Wikis




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Internet Telephony

! Use of Internet data connections to exchange voice and fax data »  these have traditionally been carried over the public

switched telephone network

! Based on Voice over IP (VOIP) to be used over the Internet »  being deployed on internal corporate networks and via

the Internet

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Internet Telephony What's Needed

! Hardware »  SIP (Session Initiation Protocol) client software on a

computer »  a (non-traditional) hardware IP phone OR »  ATA (Analog Telephony Adapter) plus traditional

phone (e.g., Vonage)

! VoIP service provider »  May charge extra for outgoing landlines and mobiles

!  ISP and broadband connection to the Internet

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Internet Telephony Without Phones

! Many instant messaging applications also offer video and voice chat »  so it's essentially Internet telephony without a real

phone

! Examples »  Skype »  AIM »  Google Talk, phone calls via Gmail »  Truphone – works on the iPhone and other mobile

phones

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! Blogs ! Wikis




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Google Documents

!  Online place to create, edit, store, share, collaborate on documents »  documents (like Word) »  spreadsheets (like Excel) »  presentations (like PowerPoint) »  PDFs

!  Alternative to collaborating by emailing attachments

!  “Google Docs in Plain English” video »  http://www.youtube.com/watch?v=eRqUE6IHTEA

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Three Questions

! What is the Internet?

! Who uses the Internet?

! What applications run over the Internet?

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Homework 1

! Design your own Internet application

! One-page description »  must be something new

! Mock-up (drawing, PPT, …) of application

! Due next Tuesday at beginning of class »  see online class schedule for details

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Up Next…

! Web Applications »  Internet Search and Webpage Accessibility

! Whirlwind Intro to the Internet »  protocols »  network edge