1. COS 125 DAY 4

2. Agenda Questions from last Class?? Using blackboard’s assignment section Today’s topics Communicating on the Internet Assignment #1 Due Assignment #2 Posted Due Feb 15 Quiz #1 on Feb 12 Chap 1-26 20 M/C, 4 short essays, One extra credit Question 60 Min, open book, open notes

3. Communicating on the Internet How email works How email Spam works How Newsgroup work How Internet Chat and Instant Messaging Work How Internet Phone calls work How Blogging and RSS works

4. email Animation from www.learnthenet.com

5. How email works Most heavily used feature on the Internet Advantages Asynchronous Ubiquitous Can be made Secure (almost too secure) Disadvantage Impersonal Ubiquitous Insecure (non-confidentiality) Virus, Macros, Trojans Horses Lack of a centralized directory

6. How email works To send email You need an email account someone@somewhere.com With an email you can send Plain text Formatted text (RTF) HTML Attachments Email Demo from www.learnthenet.com

7. Outlook email client

8. Where is email is sent? How does your email server know where to send mail? DNS MX records Every Domain has an MX record that tells you what Mail server is responsible for that domain’s email

9. Mail to and from

10. Email end to end

11. Mailing Lists A group of people that has similar interests Each person joins the “group” which has an email address assigned group1@lists.comgroup1@lists.com When you send and email to group1@lists.com everyone that joins the group gets the email group1@lists.com Two types of Mailing lists Moderated Unmoderated Mailing List Demo from www.learnthenet.com

12. Making email secure Encryption Scramble and then descramble the message using a secret code Most encryption uses two “keys” One to scramble The other to unscramble Some only use one Encryption demo from Persits.com Encryption Demo from learnthenet.com

13. Public Key Encryption for Confidentiality Encrypt with Party B’s Public Key Party A Party B Decrypt with Party B’s Private Key

14. Public Key Encryption for Confidentiality Decrypt with Party A’s Private Key Party A Encrypt with Party A’s Public Key Party B

15. Getting Public keys

16. Using Encryption in email

17. LDAP White pages for computer users LDAP client <> LDAP Server Client asks for an address Server return the address Built into Windows 2000 and XP

18. How SPAM works SPAM is unsolicited Junk email Why is this done CHEAP mass marketing Junk postal mail costs at least $0.20 per mailing Spam cost around $100 per million emails sent or $0.0001 per mailing Origin of the word Spam http://www.odul.com/spam/

19. Tricks of the SPAMMER trade http://www.marketing-2000.net/ Getting email address Directories Newsgroups Buy from other spammers Build a web site to collect them Sending emails Manipulate headers to hide sending info Uses some else's email sever Open SMTP relay’s

20. Stopping Spammers Laws don’t work Can’t prosecute what you can’t catch Laws are tied to jurisdictions, Spammers aren’t Spam laws Special anti-spam software Spammer just get “trickier” and by pass software Blocking places that send spam Since spammer don’t use their own mail servers you run the risk of blocking legitimate email Best practice –Get more email addresses Get an email address just for spammers me@hotmail.com Protect important emails by using sparingly One just for family & friends One just for work or school

21. Newsgroups USENET is the worlds biggest discussion forum. Collections of newsgroup of many subjects Best place to see the groups is http://groups.google.com Demo of newsgroups from Learnthenet.com Just like mailing lists newsgroup can be Moderated Unmoderated

22. How Usenet Servers works Servers replicates newsgroups to each other. Users can use any of the Usenet Servers to post and receives Postings.

23. Problems with USENET With the advent of instant messaging, MSN, AOL and Yahoo groups, blogs and other new internet inventions Usenet isn’t used by much of the Internet population Many ISP’s don’t support USENET A lot of what’s “bad” with the internet is on USENET..the equivalent of the Internet “bad part of town” Hate groups & terrorists Pornography Hackers and crackers Perverts & pedophiles Better places for discussions groups MSN groups Yahoo groups

24. How Internet Chat works Live keyboard conversation on the Internet Most popular is Internet Relay Chat Topic are channels (Chat Rooms) Chat works on Client/Server model Users are on clients The chat room is on a server There are many proprietary Chat solutions Blackboard

25. How IRC works Images from http://www.nur.ac.rw/chat.htm

26. Chat stuff Acronyms brb = be right back bbl = be back later btw = by the way np = no problem lol = laughing out loud re = hi again, as in 're hi' rotfl = rolling on the floor laughing bbiaf = be back in a flash ttfn = ta ta for now imho = in my humble opinion j/k = just kidding wb = welcome back

27. Emoticons :) Smile :-) Basic Smile ;-) eye wink :-( sad :-I Indifference :-> Sarcastic >:-> Diabolic (-: left handed %-) Drunk 8-) Uses glasses B:-) Sunglasses on head B-) dark sunglasses 8:-) little girl :-{) Mustache :-{}painted mouth {:-)with hair :-^) with flu :-)^ choking :'-( crying :-@ shouting :-& cant talk -:-) punk |:-) fall sleep :-O waking up 0:-) angel :-D laughing :-X lips seal :-Q smoker :-/ skeptic C=:-) chef @= nuclear bomb *:O) clown [:-) using walkman (:I egghead @:-) with turban X-( just died :] friendly smile :D laugh :( again sad :O shouting [] hugs :* kisses :*, ;* more kisses :*, :*, :*, :*, more and more kisses

28. Instant Messaging Differs from chat in that it is one-to-one Chat one-to-many Four popular software applications that have little to no interoperability MSN Messenger ® AOL Instant Messenger ® ICQ ® YAHOO! Messenger ® One instant messenger is trying to become protocol independent Miranda supports the four listed above

29. How Instant Messaging works Login to messaging server (AOL, MSN) Send your buddy list to server Server tells you which of your buddies are logged in Select on inline buddy to talk to Some systems connect buddy to buddy to chat (MSN) Other run all chats through the server (AIM)

30. How Internet Phone Calls Work This is using the Internet to replace the Public Switched Telephone system Save money on long distance Called Voice over IP or VoIP Converts Voice (analog) to digital packets and vise versa Digital packets sent over the internet

31. PC Phones PC to PC PC to Regular Phone Regular Phone to Regular Phone Images from http://www.pc-telephone.com/

32. PBX-PBX IP Telephony Ordinary Telephone Ordinary Telephone Frame Relay, ATM, or the Internet IP Packet PBX with IP Telephony Module PBX with IP Telephony Module

33. IP Phones from Cisco

34. How Skype works http://www.englishflow.net/en-skype.html http://share.skype.com

35. Hoe Skype Works http://images.businessweek.com/mz/04/44/0444_60inftec.gif

36. Blogging http://computer.howstuffworks.com/blog.htm A blog is any or many of the following online journal written by an individual method a self publication a diary career building – letting everyone know about your talents and ideas career suicide – venting about a company or person, taking a controversial position, blogging at work way to make money Get notice by search engines Bloggers require readers The update problem- when do the readers know that there is new dialogue on the blog

37. RSS Really Simple Syndication Addresses the “update” problem Two (or three) parts Publisher (feed) – special XML files contains title, description and link to the actual data Reader – Finds and reads the XML files and “pulls” the xml files. http://blogspace.com/rss/readers Aggregators – pulls several RSS feeds together

38. http://searchengineland.com/070904-141823.php

39. http://journal.plasticmind.com/tech-tips/feed-tip-for-facebook-status-junkies/

40. Maine’s Anti-Hacker laws 432. Criminal invasion of computer privacy 1. A person is guilty of criminal invasion of computer privacy if the person intentionally accesses any computer resource knowing that the person is not authorized to do so. [1989, c. 620 (new).] 2. Criminal invasion of computer privacy is a Class D crime. [1989, c. 620 (new).] §433. Aggravated criminal invasion of computer privacy 1. A person is guilty of aggravated criminal invasion of computer privacy if the person: A. Intentionally makes an unauthorized copy of any computer program, computer software or computer information, knowing that the person is not authorized to do so; [1989, c. 620 (new).] B. Intentionally or knowingly damages any computer resource of another person, having no reasonable ground to believe that the person has the right to do so; or [1989, c. 620 (new).] C. Intentionally or knowingly introduces or allows the introduction of a computer virus into any computer resource, having no reasonable ground to believe that the person has the right to do so. [1989, c. 620 (new).][1989, c. 620 (new).] 2. Aggravated criminal invasion of computer privacy is a Class C crime. [1989, c. 620 (new).]

41. For next class Read through Chapter 26 (page 184) Quiz 1 on Feb 12 (one week from today) Extra Credit Question on Next exam How many Hackers have been arrested in Maine? Can you name any successful prosecutions of Hackers in the state of Maine? What is the problem in catching and prosecuting Hackers in Maine?