1
00:00:00,000 --> 00:00:04,811
[MUSIC]

2
00:00:04,811 --> 00:00:10,511
What actually happens in between typing in
teamtreehouse.com and seeing the website?

3
00:00:10,511 --> 00:00:14,684
If point a is the browser on your
computer, and point b is a web server

4
00:00:14,684 --> 00:00:20,080
hosting teamtreehouse.com, everything in
between is the cloud, right?

5
00:00:20,080 --> 00:00:21,800
Well, yes and no.

6
00:00:21,800 --> 00:00:25,950
In between each browser request and server
response are one or

7
00:00:25,950 --> 00:00:29,810
multiple pieces of software, most of them
speaking to each other using

8
00:00:29,810 --> 00:00:35,490
a common protocol called HTTP, or the
Hypertext Transfer Protocol.

9
00:00:35,490 --> 00:00:37,820
Let's start with an overview of how the
Web works, and

10
00:00:37,820 --> 00:00:40,830
then explore each step individually.

11
00:00:40,830 --> 00:00:46,250
Every website you've browsed started with
a client sending a request to a server.

12
00:00:46,250 --> 00:00:50,120
A client is anything that can request a
resource on the web.

13
00:00:50,120 --> 00:00:54,450
A few examples are computers, laptops,
phones, and tablets.

14
00:00:54,450 --> 00:00:58,530
But even software programs themselves can
be clients.

15
00:00:58,530 --> 00:01:03,940
When a client, you and your computer,
types a URL into the address bar,

16
00:01:03,940 --> 00:01:06,080
you are sending a request to a server.

17
00:01:07,290 --> 00:01:13,060
The internet is a net of computers all
connected together by various cables.

18
00:01:13,060 --> 00:01:15,910
It's made up of wires, routers, switches
and

19
00:01:15,910 --> 00:01:19,280
satellites, connecting the network of
servers together.

20
00:01:20,300 --> 00:01:23,560
These servers can perform a lot of tasks.

21
00:01:23,560 --> 00:01:28,150
A few server examples are web servers that
host web sites,

22
00:01:28,150 --> 00:01:32,820
domain name servers that connect domain
names with IP addresses, or

23
00:01:32,820 --> 00:01:37,120
mail servers that send and accept email
messages.

24
00:01:37,120 --> 00:01:39,660
All of these things are considered part of
the internet.

25
00:01:41,560 --> 00:01:47,300
Housed on servers are the files, folders
and media that make up webpages.

26
00:01:47,300 --> 00:01:51,090
These files, folders and media are all
software and

27
00:01:51,090 --> 00:01:54,080
are what we're talking about when we say
the web.

28
00:01:55,320 --> 00:02:00,300
The web is the software that makes up
websites, applications,

29
00:02:00,300 --> 00:02:04,600
games, wikis and videos that you can
access on a web browser.

30
00:02:05,870 --> 00:02:09,590
As you know, there are a lot of different
web browsers out there.

31
00:02:09,590 --> 00:02:13,480
Safari, Firefox, Chrome, and Internet
Explorer to name a few.

32
00:02:13,480 --> 00:02:20,420
There are also many types of clients,
mobile phones, apps, and games.

33
00:02:20,420 --> 00:02:24,500
In order for everyone to play nicely
together, they have to speak the same

34
00:02:24,500 --> 00:02:31,250
language, and that language is called
HTTP, or Hypertext Transfer Protocol.

35
00:02:31,250 --> 00:02:34,830
Nearly all HTTP requests start with you

36
00:02:34,830 --> 00:02:39,130
typing in a domain name like
teamtreehouse.com.

37
00:02:39,130 --> 00:02:43,840
Servers, however, use numbers to locate
each other, not words.

38
00:02:43,840 --> 00:02:49,391
These numbers are called IP addresses and
work similarly to how phone numbers work,

39
00:02:49,391 --> 00:02:53,631
with each IP address pointing to a
particular server on the Web.

40
00:02:53,631 --> 00:02:58,992
The service in the middle, between the
domain name you type in and

41
00:02:58,992 --> 00:03:05,151
the IP address used by the server, is
called a Domain Name Server, or DNS.

42
00:03:05,151 --> 00:03:11,399
Once the DNS finds the IP address or phone
number you asked for with the domain name,

43
00:03:11,399 --> 00:03:16,231
it rushes your request along to the server
hosting the website.

44
00:03:16,231 --> 00:03:21,619
For now, we can think of this request as a
stamped, self-addressed envelope

45
00:03:21,619 --> 00:03:27,350
sent to the website's IP with a return
address of your computer's IP.

46
00:03:27,350 --> 00:03:31,209
When the envelope is delivered to the
server hosting the website,

47
00:03:31,209 --> 00:03:36,380
the server sends the envelope back to you
with the website you wanted.

48
00:03:36,380 --> 00:03:42,150
When this happens, the HTTP trip is over
and you have the thing you asked for.

49
00:03:42,150 --> 00:03:46,930
Now that took a long time to explain, but
usually this all happens very quickly,

50
00:03:46,930 --> 00:03:50,580
like, in under a second, and it's getting
faster all the time.

51
00:03:50,580 --> 00:03:54,850
Now that we're familiar with the process
of what happens when we surf the web,

52
00:03:54,850 --> 00:03:57,090
let's break down each step in more detail.