IE Class - Unit 1 - Lesson 3x - CoachSib

warbarnacleSecurity

Nov 5, 2013 (4 years and 7 days ago)

102 views

Unit 1


Lesson 3

Introduction To The Internet


IE Class


Conceived in 1960’s to communicate between military
and Government should the cold war get out of control



Wanted it to work even if part of it was destroyed



US Department of Defense's Advanced Research


Projects Agency (ARPA) began working with the RAND
Corporation



1965 Developed Arpanet, the first internet prototype



1969


Connected 4 computers (Stanford, UCLA, U.C.
Santa Barbara, Utah) “Are you getting this?”



1992 US Government turned development of the Internet
over to the private sector



HOW THE INTERNET GOT STARTED



I
NTERNET

B
ACKBONE



Physical Networking of Internet (Usually fiber
optics and satellites)



Data Slowed down by networks, hubs, routers,
solar interference



Fiber Optics carries more data, further and faster


I
NTERNET

C
OMMUNICATIONS

S
TANDARDS



Client
-
Server Model


Servers Contain Data and Clients request the
data


Protocols


Rules for transmitting data over Internet


Allows different operating systems to
communicate with each other


Transmission Control Protocol (TCP)


No restrictions or royalties


Based on Arpanet concept


Info is sent over the Internet in packets no bigger than 1500
characters


I
NTERNET

C
OMMUNICATIONS

S
TANDARDS



TCP/IP (Internet Protocol)


Ever computer on the Internet has Internet
Protocol Address


TCP/IP allows info to travel across the
Internet till it reaches your computer


Each packet contains the IP address of both
sending and receiving computer


Packets may travel various paths to get to
your computer


I
NTERNET

C
OMMUNICATIONS

S
TANDARDS



Protocol for handling info for various applications
(Not just web pages)


World Wide Web (Hyper
-
Text Transfer
Protocol


HTTP)


E
-
mail (Simple Mail Transfer Protocol


SMTP
or POP3)


Translate host name to domain server
(Domain Name Service


DNS)


Remote Terminal Access (Telnet or Secure
Shell)


I
NTERNET

C
OMMUNICATIONS

S
TANDARDS



Ports


Ports


doors info takes to get into your
computer


Web Browsers


Port 80


Email


Port 25


Ports are opened and closed like doors


Malicious programs try access open ports


Firewalls keep ports secure


D
OMAIN

N
AME

S
ERVICES



Each Web page and document on Internet have
specific addresses (IP)


Uniform Resource Locator (URL)


URL is written in a specific format like a letter


Protocol://IP address/directories



Domain Names take place of address for ease


Names must be registered with DNS


DNS matches Domain Name with IP Address


D
OMAIN

N
AME

S
ERVICES



Domain Name Look Up


Performed when you type Domain Name and
hit enter


Domain sent to server that matches Domain
Names to IP addresses


Request is sent to appropriate IP


D
OMAIN

N
AME

S
ERVICES



Host Domain



receives request for info you want to look at


Packets info and send to client


Each packet may travel different path


Packets are collected at client and reassembled


Notice sent to host computer that packets were
received


If no notice is received host resend packets


D
OMAIN

N
AMES



Determined by type of Organization by Top Level Domain
(TLD)


Extension separated by a period after the name


Categories


Country Code Domains


Used by governments and organizations of the
countires


Generic Domains


Used by general public


.com (Commercial)


.net

(Network)


.org (Non
-

Profit organization)


.
edu

(Educational)


.
gov

(US Gov organization)


.mil (US military)


To get website online


Webserver

to host website


Provide IP Address


Register Domain Name with DNS


DNS will link Domain Name with IP Address


T
HE

W
ORLD

W
IDE

W
EB



Tim Berners
-
Lee


1989 working CERN Laboratories (Nuclear
Research) Geneva Switzerland


Wanted way to share research without having to
load onto each computer


Created concept of “Linking” computer together


Was using Standard Generalized Markup
Language (SGML)


Not easy to use


Did not provide linking one doc to another


Developed Hyper
-
text language (HTML) for
linking text


Many institutions joined to share info and offer Internet to
public


T
HE

W
ORLD

W
IDE

W
EB



Originally called “Information Super Highway”


Slated as end of Privacy, fall of Society


Prodigy Communication Company


One of First to offer WWW to general public


Many Companies Joined in offering WWW
service


CompuServe, AOL, MSN


Mailed Thousands of CD’s so public could
connect to WWW


W
EB

B
ROWSERS



Web Browsers view HTML documents


Mosaic


1
st

to provide web browser


Later became known as Netscape


2002


Netscape basically extinct


1998 created Mozilla Foundation to make
Open Source Web Browser


Now called Mozilla Firefox


February 2009 held 21% of Market share


1995
-

Microsoft released Internet Explorer (IE)


S
EARCHING

F
OR

I
NFORMATION

O
NLINE



Search Engines most common tool (Google,
Yahoo, Bing)


Search Web for documents on your search


You enter a Query (Key word) into a search
form which searches it’s database for
documents on your search


Use programs called spiders


Follow links on web pages and saves data about the pages


Called Indexing


Work constantly


If page is not indexed it will not show up in search


No consensus on “Best” engine


K
EYWORD

S
EARCHING



Search engine will return all pages containing
word used in search


Returns millions of results


Methods for narrowing results


Boolean search


Allows you to use and omit specific words


Use “And, Or, Not”


Some engines automatically add “AND”
between words in search


Others Assume they are phrase


S
UBJECT

D
IRECTORY



Organized by humans not spiders


DMOZ, Google Subject Directory, Yahoo Subject
Directory


C
LIENT
-
S
ERVER

A
PPLICATIONS

AND

W
EB

A
PPLICATIONS



Some software you install on your computer


Web Application software runs through web page
interface


Message board, Java script game, registration
page


Client
-
Server Application


Runs on client computer


Interacts with server somewhere else


i.e. web browser


T
RENDS

IN

W
EB

T
ECHNOLOGY



Internet designed for open growth


Architecture is simple and flexible


No specific person “Owns” the internet


Its all open source (Available to anyone)


Originally designed to transmit text..now grown to much more


Web 1.0


referred to the connectivity of content and documents on
the Internet


Web 2.0


Interactive web pages


Customized for the specific user


i.e. Social Networking


Graphics give fluid, smooth look


Location Based Web Services


Work with GPS to offer services in your area


Portable Navigation