COS 125

DAY 4

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

Communicating on the Internet

How email worksHow email Spam worksHow Newsgroup workHow Internet Chat and Instant

Messaging WorkHow Internet Phone calls workHow Blogging and RSS works

email

Animation from www.learnthenet.com

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

How email works

To send emailYou need an email accountsomeone@somewhere.com

With an email you can sendPlain textFormatted text (RTF)HTMLAttachments

Email Demo from www.learnthenet.com

Outlook email client

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

Mail to and from

Email end to end

Mailing Lists

A group of people that has similar interests Each person joins the “group” which has an

email address assigned group1@lists.com When you send and email to

group1@lists.com everyone that joins the group gets the email

Two types of Mailing lists Moderated Unmoderated

Mailing List Demo from www.learnthenet.com

Making email secure

EncryptionScramble and then descramble the

message using a secret codeMost encryption uses two “keys”

One to scrambleThe other to unscramble

Some only use oneEncryption demo from Persits.comEncryption Demo from learnthenet.com

Public Key Encryption for Confidentiality

Encrypt withParty B’s Public Key

Party A Party B

Decrypt withParty B’s Private Key

Public Key Encryption for Confidentiality

Decrypt withParty A’s Private Key

Party A

Encrypt withParty A’s Public Key

Party B

Getting Public keys

Using Encryption in email

LDAP

White pages for computer usersLDAP client <> LDAP Server

Client asks for an addressServer return the address

Built into Windows 2000 and XP

How SPAM works

SPAM is unsolicited Junk emailWhy is this done

CHEAP mass marketingJunk 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/

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

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

Newsgroups

USENET is the worlds biggest discussion forum.Collections of newsgroup of many subjectsBest place to see the groups is

http://groups.google.comDemo of newsgroups from Learnthenet.comJust like mailing lists newsgroup can be

ModeratedUnmoderated

How Usenet Servers works

Servers replicates newsgroups to each other.

Users can use any of the UsenetServers 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 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

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

How IRC works

Images from http://www.nur.ac.rw/chat.htm

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=:-) 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

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 toSome 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 systemSave money on long distanceCalled Voice over IP or VoIP

Converts Voice (analog) to digital packets and vise versaDigital packets sent over the internet

PC Phones

PC to PC

PC to Regular Phone

Regular Phone to Regular Phone

Images from http://www.pc-telephone.com/

PBX-PBX IP Telephony

OrdinaryTelephone

OrdinaryTelephone

Frame Relay, ATM, orthe Internet

IPPacket

PBX withIP Telephony Module

PBX withIP Telephony Module

IP Phones from Cisco

How Skype works

http://www.englishflow.net/en-skype.html

http://share.skype.com

Hoe Skype Works

http://images.businessweek.com/mz/04/44/0444_60inftec.gif

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

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

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

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

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 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?