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In this module, we are going to be learning about the ins and outs of the web. Navigating
the web appears on the surface as a simple thing. Just turn on your computer, get connected
to the Internet, open up a browser, go to Google.com and enter a search query to get
what you’re looking for. But there’s much more to it than that. For example, the web
has its own lingo. What is a cookie? What is TCP/IP? Why does everyone keep saying “it’s
in the cloud”? So this section is about getting into the language and grammar of the
web. We’ll start by learning about internet protocol
(or IP) and the domain name system (or DNS). First, let’s clear up one thing: URL. URL
stands for Uniform Resource Locator. It’s a character string that reference an Internet
resource such as a website. I’m sure you know what a web browser is
but just in case, a browser is a software application that lets you navigate the Internet.
It’s the tool you are using right now to access the video in this learning management
system. The learning management system is a program that lives on the special computers
called servers because they serve files and webpages and the like to folks who ask for
them. How do people ask for these files from the servers? They do so using a web browser.
The most popular browsers in America include Google’s Chrome, Microsoft’s Internet
Explorer (that’s the E that shows up on your desktop unless you’re using a Mac),
or Mozilla’s Firefox, or Apple’s Safari.
So how does your browser find the right web page when you type an URL into its address
bar? Every URL has its own numbered Internet Protocol or IP address. An IP address looks
something like this:
An IP address is a series of numbers that tells us where a particular device is on the
Internet network, be it the google.com server or your very own computer. It’s a little
like your phone number: just as the phone number tells an operator which house to route
a call to so that it reaches the person you’re trying to reach, an IP address tells your
computer which other device on the Internet to communicate with – to send data to and
get data from. Data like web pages.
Your browser doesn’t automatically know every IP address for the 40 billion devices
on the planet that are connected on the Internet. It has to look each one up, using something
called the Domain Name System or DNS. The DNS is essentially the phone book of the Web:
while a phone book translates a name like “Domino’s Pizza” into the right phone
number to call, the DNS translates an URL or web address into the right IP address to
contact (like “74.125.19.147”) in order to get the information that you want. So when
you type “google.com” into your web browser, the browser looks up google.com’s IP address
through a DNS and contacts it, waits for a response to confirm the connection and then
sends your request for google.com’s web page to that IP address. Google’s server
at that IP address will then send back the requested web page to your computer’s IP
address for your browser to display. Now, in many ways, retrieving and loading
a web page in the browser is not unlike making a phone call. When you make a phone call,
you’d probably look up the number, dial, wait for someone to answer, say “hello”
and wait for a response before you start the conversation. Sometimes you have to redial
if there are problems connecting. On the web, a similar process happens in a split second;
all you see is that you’ve typed “www.google.com” into the browser and the Google homepage appears.
Now I mentioned IP addresses. The IP addresses have corresponding URLs. A good way to think
of it like this: Your house or apartment has a street address.
Let’s say it 6401 Linda Vista Blvd. (that’s our address here at the San Diego County Office
of Education). If a person looked up that address in a map, they would be able to find
you and navigate to your house. But your house also can be found through more precise coordinates
like it longitudinal and latitudinal location on the plant. For example, my office is located
at 32 degrees latitude 46 minutes and -117 degrees longitude 10 minutes. So in this analogy,
my street address is the URL. Like the URL of a website and my latitude and longitude
coordinates are my IP address. Of course it’s not a perfect analogy but it’s another way
of thinking about how URLs and IP address differ but serve the same purpose—to locate
websites and networked devices. So what’s your computer’s IP address?
Find out by checking out the web links just below this video. Then, if you’d like to
find the IP address of a particular website like your school’s website or a site you
frequent, take a look at the second link below.