
8
00:01:41,242 --> 00:01:45,681
Now exactly what happened when you clicked on that link?  

  

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00:01:46,447 --> 00:01:48,447
You started a flow of information.  


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00:01:48,718 --> 00:01:52,170
This information travels down to your own personal mail-room where Mr. IP packages it,

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00:01:53,461 --> 00:01:56,366
labels it and sends it on its way.

12
00:01:56,964 --> 00:02:01,403
Each packet is limited in its size. The mail-room must decide how to divide the information and how to package it. 
 

13
00:02:03,296 --> 00:02:12,262
The IP packet now needs a label, containing important information such as sender's address, receiver's address and the type of packet it is. 

14
00:02:28,206 --> 00:02:36,604
Because this particular packet is going out onto the Internet, it also gets an address for the Proxy Server 

15
00:02:40,177 --> 00:02:45,646
The packet is now launched onto your Local Area Network or LAN. 

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00:02:46,349 --> 00:02:53,569
This network is used to connect all the local computers, routers, printers etc. 


17
00:02:54,515 --> 00:02:58,517
The LAN is a pretty uncontrolled place and unfortunately accidents can happen 

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00:03:08,872 --> 00:03:17,852
The highway of the LAN is packed with all types of information. There are IP packets, Novell packets, Apple Talk packets  

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00:03:20,253 --> 00:03:26,058
The local router reads the address and if necessary lifts the packet onto another network.

20
00:03:26,648 --> 00:03:31,537
Ah the router. A symbol of control in a seemingly disorganized world.   


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00:03:42,692 --> 00:03:51,289
There he is..systematic, uncaring, methodical, conservative and sometimes not quite up to speed.

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But he is exact... for the most part.

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As the packets leave the router, they make their way into the corporate intranet and head for the router switch.
 
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00:04:18,852 --> 00:04:26,165
 

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00:04:44,339 --> 00:04:54,310
As packets arrive at their destination they are picked up by the network interface, ready to be sent to the next level. 

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In this case, the proxy.

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The proxy is used by many companies as a sort of "middleman" in order to lessen the load on their Internet connection.

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00:05:09,436 --> 00:05:14,819
We can see that the packet are all of various sizes, depending on their content. 

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00:05:34,015 --> 00:05:39,867
The proxy opens the packet and looks for the WEB address or URL.  

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Depending upon whether the address is acceptable…the packet is sent on to the Internet.

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00:05:51,083 --> 00:06:00,818
There are, however, some addresses which do not meet with the approval of the proxy

32
00:06:03,000 --> 00:06:06,648

  
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00:06:09,000 --> 00:06:13,013
For those who make it, it's on the road again.

34
00:06:23,536 --> 00:06:27,668
Next up - the Fire Wall.    


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00:06:30,795 --> 00:06:33,096
The corporate Fire Wall serves two purposes.

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00:06:34,760 --> 00:06:39,420
It prevents some rather nasty things from the Internet from coming into the intranet.

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00:06:39,978 --> 00:06:44,509
And it also can prevent sensitive corporate information from being sent out to the Internet.

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Once through the fire wall, a router picks up the packet and places it on to a much narrower road or band-width, as we say. 


39
00:06:56,985 --> 00:07:00,896
Obviously, the road is not broad enough to take them all. 

40
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Now you might wonder what happens to all those packets which don't make it along the way. 
 

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00:07:06,795 --> 00:07:14,789
Well, when Mr. IP doesn't receive an acknowledgment that a packet has been received in due time, he simply sends a replacement packet. 

42
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We are now ready to enter the world of the Internet. A spider web of inter-connected networks which spans our entire globe. 

43
00:07:28,185 --> 00:07:32,396
Here, routers and switches establish links between networks. 
 

44
00:07:33,246 --> 00:07:39,473
Now, the Net is an entirely different environment than you'll find within the protected walls of your LAN.



45
00:07:40,811 --> 00:07:46,470
Out here, it's the Wild West. Plenty of space, plenty of opportunities, plenty of things to explore and places to go. 

46
00:07:47,280 --> 00:07:54,758
Thanks to very little control and regulation new ideas find fertile soil to push the envelope of their possibilities.  


47
00:07:55,472 --> 00:07:59,189
But because of this freedom, certain dangers also lurk. 

48
00:07:59,750 --> 00:08:03,493
You'll never know when you'll meet the dread Ping Of Death

49
00:08:04,315 --> 00:08:07,668
 

50
00:08:12,819 --> 00:08:20,333
The paths our packets take maybe via satellite, telephone lines, wireless or even trans-oceanic cable. 

51
00:08:21,323 --> 00:08:27,428
They don't always take the fastest or shortest routes possible, but they probably will get there - eventually. 

52
00:08:28,419 --> 00:08:35,185
Maybe that's why it's sometimes known as the World Wide Wait. 
    

53
00:08:36,297 --> 00:08:42,145
But when everything is working smoothly, you can circumvent the globe 5 times over, at the drop of a hat   

54
00:08:47,305 --> 00:08:50,916
Near the end of our destination, we'll find another Fire Wall. 


55
00:08:52,209 --> 00:09:04,435
Depending upon your perspective as a data packet, the fire wall can be a bastion of security or a dread adversary. 


56
00:09:05,373 --> 00:09:12,856
The Fire Wall is designed to let in only those packets that meet its criteria. 

57
00:09:14,101 --> 00:09:21,342
This wall is operating on ports 80 and 25. All attempts to enter through other ports are closed for business. 


58
00:09:35,281 --> 00:09:46,436 
Port 25 is used for mail packets, while port 80 is the entrance for packets from the Internet to the Web server. 

59
00:09:47,897 --> 00:09:51,691
Inside the fire wall, packets are screened more thoroughly,  


60
00:09:52,504 --> 00:09:58,503
some packets make easily through "customs" while others look just a bit dubious. 

61
00:09:58,853 --> 00:10:05,178
The Fire Wall officer is not easily fooled, such as when this ping of death packet   

62
00:10:05,161 --> 00:10:10,581
tried to disguise itself as a "normal" ping packet.

63
00:10:15,071 --> 00:10:20,731
For those packets lucky enough to make this far, the journey is almost over.

64
00:10:22,813 --> 00:10:27,909
It's just to line up on the interface to be taken up into the web server. 
 

65
00:10:29,683 --> 00:10:34,313
Nowadays, a web server can run on many things.

66
00:10:34,986 --> 00:10:38,853
>From a mainframe, to a web-cam to the computer on your desk. Or why not your refrigerator? 

67
00:10:44,817 --> 00:10:50,526
Remember this is the Dawn of the Net - almost anything's possible. 


68
00:10:54,996 --> 00:10:59,542
One by one, the packets are received, opened and unpacked.   
 
69
00:11:03,433 --> 00:11:09,689


70
00:11:09,955 --> 00:11:14,315
is sent onto the Web server application.  

71
00:11:18,567 --> 00:11:29,554
The packet itself is recycled. Ready to be used again. And filled with your requested information.  

72
00:11:35,361 --> 00:11:39,335
Addressed and sent out on its way back to you.

73
00:11:40,099 --> 00:11:46,549
Back past the fire walls, routers, and on through the Internet.

74
00:11:50,625 --> 00:11:54,443
Back through your corporate fire wall 

75
00:11:57,804 --> 00:12:00,908
and onto your interface. 


76
00:12:01,714 --> 00:12:05,958
Ready to supply your web browser with the information you requested. 


77
00:12:08,933 --> 00:12:14,113
That is - this film.  

78
00:12:17,839 --> 00:12:29,661
 
Now isn't that a happy ending? 