websites & the internet
Post on 13-Feb-2017
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what is the internet?
goalsformalize your understanding of the way the internet and websites work
internet structure and protocolconnecting through the cloud
1
internet, you say? what is an internet?
◦ global network of connected devices
◦ client: a computer/program used to access information or services on another computer/program
◦ server: a computer/program that provides information or services to another computer/program
how does one connect to this “internet”?
◦ LAN (local area network)◦ ISP (internet service provider)◦ IP address (internet protocol)
internet addresses
the “cloud
”
client 1.22.33.
4
server 5.66.77.
8
speaking the same language
◦ router: directs data to the appropriate place
◦ TCP/IP (transmission control protocol/internet protocol)
◦ TCP = what is it◦ IP = where is it going
data transfer
◦ information that is being sent is broken down into “packets” via TCP
◦ routers forward the data packets to their destination using decentralized transmission
◦ inbound packets are reassembled upon receipt via TCP
data transfer
terminal AISP/
routers on routers
terminal 2
data packets
DNSusing domains to connect users to your site, email, and more
domain nameshow humans use the internet
2
names and addresses
◦ did you know? people generally cannot retain or process information as well as computers
◦ a domain name is essentially an alias for an IP address
◦ by using the domain name system, domains can be mapped to a number of internet resources and functions
what’s in a name?
◦ URL: http://www.buzzfeed.com/quizzes
◦ prefix: http◦ subdomain/host name: www.◦ domain: buzzfeed.com◦ name: buzzfeed◦ extension/top-level domain: .com◦ subfolder: /quizzes
names and addresses
◦ URL: your request◦ prefix: what type of resource you
are looking for◦ subdomain/host name:
subsection of a domain◦ domain: the server you want to
access◦ subfolder: the location of your
request on the server
name serversthe translators of the machine world
3
finding a resolution
◦ when you enter a domain name into your browser, you issue a request for information
◦ that request is transmitted to a domain name server that directs your computer to where that information can be found
◦ packets are sent back to your IP address from a web server
web/mail servers v name servers: dawn of justice
◦ name servers: contain information related to the location of resources associated with a domain
◦ web servers: house site content
◦ mail servers: handle and store messages being relayed to or from a domain name
you. look. fetching.
your computer
name server
web server
data
you. look. fetching.
your computer
name server
web server
data
binary view
yes no
are you connected to the internet?
HTTP request sent from your IP address
error displayed for no internet connection
does the domain exist? request is routed to the domain name server
browser error displayed for failure to resolve
domain
is there a website associated with the
domain?
request is forwarded to the site’s IP
address/web serveruser is directed to a
parking page
is there a page located at the requested URL?
web server packets returned and interpreted
by browser404 error displayed for
page not found
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