COS 125 DAY 4

Agenda Questions from last Class?? Today’s topics Communicating on the Internet Assignment #1 Corrected 13 A’s, 3 Non-submits, 1 MIA Assignment #2 will be posted next class Quiz #1 on Feb 3 (instead of Feb 10) Chap M/C, 4 short essays, One extra credit Question 60 Min, open book, open notes

Lenox Globe The Lenox Globe in the collection of the New York Public Library

Communicating on the Internet How works How Spam works How Newsgroup work How Internet Chat and Instant Messaging Work How Internet Phone calls work

Animation from

How 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

How works To send You need an account With an you can send Plain text Formatted text (RTF) HTML Attachments Demo from

Outlook client

Where is is sent? How does your 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

Mail to and from

end to end

Mailing Lists A group of people that has similar interests Each person joins the “group” which has an address assigned When you send and to everyone that joins the group gets the Two types of Mailing lists Moderated Unmoderated Mailing List Demo from

Making 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 Seidcon.com Encryption Demo from learnthenet.com

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

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

Getting Public keys

Using Encryption in

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

How SPAM works SPAM is unsolicited Junk Why is this done CHEAP mass marketing Junk postal mail costs at least $0.20 per mailing Spam cost around $100 per million s sent or $ per mailing Origin of the word Spam

Tricks of the SPAMMER trade Getting address Directories Newsgroups Buy from other spammers Build a web site to collect them Sending s Manipulate headers to hide sending info Uses some else's sever Open SMTP relay’s

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 Best practice –Get more addresses Get an address just for spammers Protect important s by using sparingly One just for family & friends One just for work or school

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

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

Problems with USENET With the advent of instant messaging, MSN, AOL and Yahoo groups, blogs and other new internet inventions Usenet isn’t used but 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

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 WebCT

How IRC works Images from

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

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=:-) nuclear bomb *:O) clown [:-) using walkman (:I with turban X-( just died :] friendly smile :D laugh :( again sad :O shouting [] hugs :* kisses :*, ;* more kisses :*, :*, :*, :*, more and more kisses

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

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)

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

PC Phones PC to PC PC to Regular Phone Regular Phone to Regular Phone Images from

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

IP Phones from Cisco

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).]

For next week Read through Chapter 28 (page 176) Assignment two will be assigned on Jan 31 Will be due on Feb 7 Quiz 1 on Feb 3 (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?