1 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/ 2 Three Questions !What is the Internet? !Who uses the Internet? !What applications run over the Internet?
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Internet Applications - Old Dominion Universitymweigle/pmwiki/uploads/CS312-F11/...How to Avoid Spam! Legislative attempts » fine spammers ! Avoid giving away your email address !
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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).
! 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
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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What applications run over the Internet?
! 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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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
! 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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What applications run over the Internet?
! 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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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
! “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