COS 125 DAY 4. Agenda Questions from last Class?? Using blackboard’s assignment section Today’s...
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Transcript of COS 125 DAY 4. Agenda Questions from last Class?? Using blackboard’s assignment section Today’s...
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
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 [email protected]
With an email you can sendPlain textFormatted text (RTF)HTMLAttachments
Email Demo from www.learnthenet.com
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
Mailing Lists
A group of people that has similar interests Each person joins the “group” which has an
email address assigned [email protected] When you send and email to
[email protected] 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
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 [email protected]
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
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
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
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?