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

Doctype  Strict  Transitional  Frameset

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

DOM  Document Object Model

Flash  Good for animations  Creates a.swf file  Can have anchors/links  Embedded into an HTML file Embedded  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 namefile extension

Webpage files  use the following extensions .html .htm .php .asp .jsp

Graphic Files Use 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 compressions zip (archive)

Protocols  What is a protocol? Just a standard way to do something Ex: 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:

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 :  Class B Used with large businesses Subnet mask:  Class C Used for small businesses and personal use Subnet mask:

FTP  File Transfer Protocol  Uses Port 21

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  tags  Can include images, text, and image maps

Tables vs. CSS  Layout of a Web page  Tables were the old way Static, didn’t display as well from one browser to another  CSS was developed to include positioning elements as well as changing the look and feel of text, graphics, etc. Uses the tags for DIViding up the page into divisions.

Domains  Common names of websites Google.com Yahoo.com espn.com murrayschools.org

ISP  Internet Service Providers Qwest DSL (Direct Sub Link) – Uses Ethernet Comcast Cable – Uses Coaxial cable

VPN  Virtual Private Network a tunnel into an network from home

Searches  Search engines Google Yahoo MSN  use quotations to search for specific phases

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 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