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Follow the course on the web at wingvillagehall.club 1
| Date post: | 13-Aug-2015 |
| Category: |
Education |
| Upload: | john-oakley |
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2
Session 4
Real Time Messaging
Instant Messages
Free Phone Calls
Video Phone Calls
Group Calling
3
Introduction
tell you “Click X to do Y“
teach you step-by-step how to send an email/Skype your son/etc
advise you on the best computer
etc…
4
Why Not?Because nobody can remember that stuff
It will be different next week
Everyone’s needs are different
“I can’t be bothered with all this medical stuff, show me how to do brain surgery”
These Sessions Will Not:
IntroductionShow you HOW to be comfortable with new technologies
Show you WHY the new ways may be advantageous for you
Help overcome the fear
Accept change
By Explaining the jargon
Introducing the concepts
Getting you to think “Oh, this is like…”
Showing you can’t “break” a computer… usually
These Sessions Will Try to:
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What are basic Instant Messages?• Real time i.e. you send it now,
your “target” sees it now.
• Like mobile phone Text - but free and on a computer
• Short text messages… but often there is no limit on message size
• Usually 1:1
• It can be a conversation
• Usually provide “Presence Awareness”
• Both sides of the conversation need to use the same protocol
What are advanced Instant Messages?
• You can also talk with your “target” - usually for FREE
• With some IM systems you can also see the “target” LIVE. It’s a VideoPhone!
• Usually 1:1
• Sometimes you can send and receive files i.e. photos, documents
• Both sides of the conversation need to use the same protocol
What are advanced Instant Messages?
• You can have a conversation with several people at the same time - its a Conference Phone
• Both sides of the conversation need to use the same protocol
Other ISP
Their Broadband
Modem
Your Broadband
Modem
Their ISP
Backbone Network
Your ISP
How does email work?
Domain Name Server
Mail Server
Relay Server
Mail Server
Other ISP
ISP - Internet Service Provider
Your email app
It’s “Store and Forward”
It’s “Store and Forward”
Your Broadband
GooglePlex
Backbone Network
Your ISP
How does Google work?
Domain Name Server
Mail Server
Relay Server
Search Engines
It’s “Conversation” oriented
Request
Response
Harry’s Modem
Sally’s Modem
How does Instant Message work?
ISP - Internet Service Provider
to:harry
It’s “Store and Forward” 34.73.46.10
It’s “Client Server” oriented
IM Server
IM Name Server
IM SessionServer
Relay Server
Relay Server
Relay Server
Relay Server
Relay Server
IM Server
Relay ServerRelay Server
Relay Server
Relay Server
Relay Server
Harry’s Modem
Sally’s Modem
IM Directory
How does Skype work?
ISP - Internet Service Provider
to:harry
It’s “Store and Forward”
Sally (moonpie)
Harry (hunkie)
34.73.46.10
It’s “Peer-to-Peer” oriented
IM Name Server
IM SessionServer
Relay Server
Relay Server
Relay Server
Relay Server
Relay Server
IM Server
Relay Server
Relay Server
Relay Server
Domain NamesInternational Company for Assignment of Network Names (ICANN) assigns the addresses to Domain Names
• e.g. • google.com • gmail.com • bbc.co.uk • facebook.com
• Registered with ICANN • ANYONE can have a Domain Name
(from £2 - £100000+ a year)
• Each Domain can have lots of Servers
• Each Server can have several Hosts i.e. Apps that provide a service
8 Main St Wing UK LE15 8SE
HQ BBC CO.UK 212.58.246.000
www.bbc.co.uk/iplayer www.bbc.co.uk/sport www.bbc.co.uk/weather
www.bbc.co.uk=212.58.246.129 news.bbc.co.uk=212.58.246.81
Snail Internet
www.bbc.co.uk/news/england
The Internet as a House
Domain Name Server (DNS)
I never use the address for anything, I use a name.
• Your computer goes to a DNS server
• It keeps a list of names and corresponding IP addresses
• It tells your computer what IP address to use
• All devices have a unique address
• like a serial number - the Media Access Code (MAC).
• Usually found on the bottom or back of the device
• Defined by manufacturer • e.g. 7A:79:19:73:D2:05
Media Access Code (MAC)
The Internet has a special networking language - the Internet ProtocolAnyone who wants to use the Internet has to have an address - the Internet Protocol (IP) address
• Google is 31.55.163.183 • The BBC is 212.58.246.104
• First part defined by the Internet Corporation for Assigned Names and Numbers (ICANN) e.g. Google 31, BBC 212 ( for big companies).
• The rest is defined by the requesting company
The Internet
The Internet - a network of computers
So to put a server on the Internet you: 1. buy a Domain name from an ISP
• wingvillagehall.club 2. ISP sends details to ICANN 3. ICANN assigns an IP address
• e.g. wingvillagehall.club has address 65.39.140.84
4. ISP adds name/address pair to its DNS server.
5. DNS entry is propagated around the world to all other DNS servers
Instant Message Protocols
Its better if we both speak the same “language”
AIM America On Line Gtalk Google ICQ mail.ru Windows Live Messenger Yahoo! Messenger Jabber Facebook Chat Skype
Instant Message Apps
Client Apps• installed on your computer
Skype Google Hangout AOL Instant Message (AIM) Yahoo IM …….
Web Apps• Nothing installed on your computer
• messages STORED on a server• lose computer, get another one and carry on
Google Hangout AIM Express ChatAB
Most IM systems are client-server
IM apps are often called IM Clients - because the client is used to connect to a server Just like eMail
Skype is Peer-to-Peer
What is Peer-to-Peer?
There is NO server! Each computer is equal to every other computer.
Each computer has a list of the computers DIRECTLY connected to it.
If the address is one of the links it uses it. If not it just sends the message to any one of the others.
Is Instant Message “safe”?
Used properly and with some caution, YES
Used without some thought and care, NO
Rules!1.Use a reputable IM providerThey filter out most bad stuff, SPAM, before you see ite.g. [email protected] [email protected] [email protected]
2.Do NOT use a cheap unknown IM providere.g. [email protected]
3.NEVER open an attachment from someone you don't know
4.NEVER give your password to anyone on line or telephone
5.NEVER give credit card details unless it is httpS://xxxxx in the address bar and then ONLY if you recognize the domain
Why? Because the bad guys will attack well-known domains because more people are using them. They are unlikely to know your private domain.
More Rules!1.Always install an anti-virus app on
Windows PCsSet it up to scan at least once a week
AVG Avast
2.Always install an anti-malware appSet it up to scan at least once a week
Malwarebytes
3.Open source apps are FREE and saferOpen source programs are written by enthusiastic nerds who are volunteers and passionate. There will be hundreds of nerds checking the app for anything evil.
I don’t want ANYONE to see my messagesToo bad!
Always assume that government agencies MAY be reading.
For most normal, law-abiding citizens you CAN keep your messages away from prying eyes
Skype encrypts all messages but for telephone calls, only to receiving exchange server
Many other IM protocols now support “Off The Record” conversations (OTR)
WWII Enigma messages can all be decoded in under a minute with a PC
The InternetPart 1
Millions of computers interconnected with a common “language”
Questions?About today
Still unanswered
Anything else
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