Understanding Internet Protocols: DHCP, DNS, and Web Technologies
Dive into the essentials of internet protocols like DHCP and DNS with this comprehensive overview. Learn how websites connect through browsers and servers, explore the intricacies of IPv4 and IPv6 addressing, and discover how domain names function in web traffic. This guide also touches on how to start your own website and the significance of web protocols such as HTTP, FTP, and SMTP. Gain insights into the historical milestones of the internet, including the contributions of key figures while understanding the impact of web crawlers and search engines.
Understanding Internet Protocols: DHCP, DNS, and Web Technologies
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Presentation Transcript
Digital Media Dr. Jim Rowan ITEC 2110
webpages and other stuff DHCP: your browser (Safari)(client) yahoo.com (server) 235.01.30.240 your computer The Internet walmart.com (server) 100.43.153.07 Domain Name System (DNS)
webpages and other stuff DHCP: 135.10.34.222 your browser (Safari)(client) yahoo.com (server) 235.01.30.240 your computer ISP The Internet walmart.com (server) 100.43.153.07 Domain Name System (DNS)
webpages and other stuff DHCP: 135.10.34.220 your browser (Safari)(client) yahoo.com (server) 235.01.30.240 http://www.yahoo.com your computer The Internet walmart.com (server) 100.43.153.07 Domain Name System (DNS) http://www.yahoo.com = 235.01.30.240
webpages and other stuff /index.html DHCP: 135.10.34.222 your browser (Safari)(client) yahoo.com (server) 235.01.30.240 http://www.yahoo.com your computer The Internet walmart.com (server) 100.43.153.07 Domain Name System (DNS) http://www.yahoo.com = 235.01.30.240
IPv4 & IPv6How many computers? • IPv4 http://en.wikipedia.org/wiki/Internet_Protocol_version_4 FF:FF:FF:FF 255.255.255.255 256 ** 4 = 4,294,967,296 computers • IPv6 http://en.wikipedia.org/wiki/IPv6_address FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF 65536:65536:65536:65536:65536:65536:65536:65536 65536 ** 8 = 3.4e+38 computers: how big is that?==>
How big is that? Circumference of the earth = 25,000 miles 25,000 x 5280 x 12 = 1,584,000,000 inches Circumference = pi x diameter Circumference of the earth = pi x 2 x radius 1584000000 = 3.14 x 2 x radius radius =252,229,299 inches Surface area of the earth = 4 x pi x radius**2 Surface area of the earth = 4 x 3.14 x 252,229,299**2 Surface area of the earth = 7.99e+17 sq inches 3.4e+38 computers / 7.99e+17 sq inches = 4.255e+20 So… that’s 4.255e+20 computers per square inch of surface area That should cover it!
Web Protocols • Protocols define the rules to be followed in a conversation • who talks first • what is acceptable to request • what are acceptable responses to a request • syntax is the actual form of each interaction • HTTP - Hyper Text Transfer Protocol • identifies it as a web page request • FTP - File Transfer Protocol • identifies it as a file that needs to be downloaded • SMTP - Simple Mail Transport Protocol • identifies it as pertaining to email
Parts of the Uniform Resource Locator URL • Three parts: • Specifies the protocol to use • HTTP • FTP • SMTP • The Domain Name • www.ggc.edu • Directory information used by the server to find the file to transmit • This can be • directory and pages • data to be handed to a program
How to start your own website • You have to buy a Domain Name from a Domain Name supplier • register.com • godaddy.com • The Domain Name supplier • pay by the year • set up domain-name-to-IP mapping • may provide some storage space for your web pages using their IP
…or to start a website • You could have your own server • Macs come with servers built in • You must have a FIXED IP from your ISP • not really but it makes life MUCH simpler • You still need a Domain Name from a Domain Name Supplier • pay by the year • set up domain-name-to-IP mapping
Looking up URLs and IPs • whois IP and Domain lookups http://ip-lookup.net/ • look up pondliner.com domain name to get IP • connect to pondliner.com using the IP address • see who owns pondliner.com • http://www.register.com/whois.rcmx
WebCrawlers • Once looked and collected email addresses to sell to spammers • Simple to do • request a page • look through the text of the page for something @ something.something • Can be defeated by using unfriendly-to-robot-code like: jrowan (at) GGC (dot) USG (dot) EDU • humans can read this just fine!
Search Engines • Web crawlers look through the web looking for keywords • Then they build a catalog of keywords • You enter a keyword in the engine • It looks at its table • It sends you the URLs associated with the keyword • GOOGLE extends this by including the number of links that point to that particular page
A brief history • Ward Cunningham • invented the WikiWikiWeb • www pages quickly editable by its users • Wiki is Hawaiian for “fast”
A brief history • Tim Berners-Lee • invented the World Wide Web • 1980 built the first web server • mid 1980s worked with hypertext • 1988- “I just had to take the hypertext idea and connect it to the TCP and DNS ideas and ta-da! the World Wide Web!” • wrote the first web browser (the client)
Randy Pausch HCI pioneer Disney Imagineering CMU: Entertainment Technology Center Creator of the Alice language
Randy Pausch The Last Lecture: Really Achieving Your Childhood Dreams http://www.youtube.com/watch?v=ji5_MqicxSo
Alan Kay’s 1968 vision of how computing COULD be: The Dynabook
Before Alan Kay at XEROX PARC… The command driven computer interface: Remember the Disk Operating System? (probably not!)
Alan Kay’s 1970’s XEROX PARC work • The Graphical User Interface GUI • But Xerox corporate didn’t think it was important
which opens the door for Steven Jobs • Macintosh 1984 • …and personal computing as we know it is born
