Delving into the Internet and Networks

In the beginning

ARPANET – set up for the military to have another network of communication

Pre-cursor to the internet

HTML

Hyper Text Markup Language Displayed through a web browser Is being replaced by XHTML

XHTML

Extensive Hyper Text Markup Language More specific than HTML Used to allow for XML XML is used to create your own tags

CSS

Cascading Style Sheet Internal or linked Control the appearance of elements in

your web page. Why cascading?

JavaScript

Must activate in Internet Explorer Used with forms for processing

information Used with CSS to animate elements

Cookies

Text file Saved on YOUR computer Used to help keep setting at a website Expiration Date

Flash

Good for animations Creates a .swf file Can have anchors/links Embedded into an HTML file Text in Flash movies not searchable

File Types

Files made up of a filename and a file extension separated by a period

myreport.doc

index.html

banner.jpg

file name file extension

Webpage files

use the following extensions .html .htm .php .asp .jsp

Graphic FilesUse the following extensions File attributes

.jpg .gif

.png .tiff

.bmp

Compressed, basic graphics Compressed, support transparency and

animation Compressed, more colors, alpha channel Not compressed, must have application to

view it Not compressed, basic image, MS Paint’s

default

Other files

.exe – executable files .pdf – acrobat reader .doc – word document .css – cascading style sheet .js – javascript file

Multimedia Files

MPEG – Graphics and Sound .avi – video .mov – quicktime movie .swf - flash movie

Compression Files

Some graphic files are compressed:jpg, gif, png

Other compressionszip (archive)

Protocols

What is a protocol?Just a standard way to do somethingEx: US mail address follows a protocol

○ Persons Name○ Street Address○ City, State, and Zip Code

The internet uses certain protocols for transferring electronic data

HTTP

Hyper Text Transfer Protocol Transfer text, anchors, graphics and

sound Uses port 80

TCP/IP

Used for sending and receiving packets via the internet

Each computer must have a separate and unique IP address

TCP is what the router uses to attach the IP address to packets being sent

IP addresses

Uses Four 3 digit numbers separated by a period

can use the numbers 0 – 255 ex:

172.0.0.1205.52.45.31

DNS Server

resolves domain names to IP addresses This is why you can type in google.com

in the URL and find the site for Google’s search engine

What’s Google’s IP address?

DHCP Server

This server will hand out an IP address to a network computer when it is booted up.

The IP can be changed with RELEASE or RENEW

Set up by your network administrator

IPCONFIG

Let’s you see your computer’s IP settings

Let’s try it

IP Classes Class A

Used with large businesses and small countries

Subnet mask : 255.0.0.0 Class B

Used with large businessesSubnet mask: 255.255.0.0

Class CUsed for small businesses and personal useSubnet mask: 255.255.255.0

FTP

File Transfer Protocol Uses Port 21

Email Protocols

SMTP – for out going mail POP3 – for in coming mail

Formats include MIME and Bin Hex and UUEncode

Access

Having rights to connect to a server or folders to FTP

Anchor

Used for Hyper links <a> </a> tags Can include images, text, and image

maps

Domains

Common names of websitesGoogle.comYahoo.comespn.commurrayschools.org

ISP

Internet Service ProvidersQwest DSL (Direct Sub Link) – Uses

EthernetComcast Cable – Uses Coaxial cable

VPN

Virtual Private Networka tunnel into an network from home

Searches

Search enginesGoogleYahooMSN

use quotations to search for specific phases

Email encoding

Uuencoding Bin Hex MIME

Bandwidth

The amount of data that can be sent through a connection

Safety - Firewall

Firewall set up to block programs from the internet from running on your computer

Virus

– sent in email attachments. Propagates itself when opened.

Worm

– does not have to be run or opened to propagate itself on a network

Trojan

Trojan – You think your running one program, but it’s doing something behind the scenes

Certificate Server

Sends an electronic “certificate” to a computer from the network to tell the computer it is a legitimate program to run

SSL

Secure Sockets Layer HTTPS Encodes the information Used with most online orders