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@@ -44,10 +44,10 @@ Before coming to the laboratory session you should have:
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Computers communicate with each other through the *Internet Protocol* (IP). When a computer sends information to another computer it is sent via *Internet Packets* that contain the Internet address of the sender computer (*source address*), and the Internet address of the receiving computer (*destination address*). Internet addresses are used to guide information from one computer to another, but, once a packet arrives to its destination, who is supposed to receive the information? Which application should receive the information?
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-The internet packets should also specify the application that sends the information and the application that should receive it. We can think that the Internet address are the mailing address of a house, and the applications that send and receive the information are the people that send and receive the correspondence. To send a letter by mail, one must specify to whom the letter is being sent. This corresponds to specify the application that receives the information. To identify the source application and the destination application, the Internet protocol uses what is known as *port numbers*. Looking at the information on the packet, the addresses and ports of the source and destination can be identified.
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+The internet packets should also specify the application that sends the information and the application that should receive it. We can think that the Internet address is the mailing address of a house, and the applications that send and receive the information are the people that send and receive the correspondence. To send a letter by mail, one must specify to whom the letter is being sent. This corresponds to specifying the application that receives the information. To identify the source application and the destination application, the Internet protocol uses what is known as *port numbers*. Looking at the information on the packet, the addresses and ports of the source and destination can be identified.
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-For instance, when your computer in the laboratory is contacting the Moodle server, the packets that carry the information from your computer to the Moodle server contain the source address of the laboratory computer and the destination address of the Moodle server. The source port is the one of your web browser and the destination port is the web server that serves Moodle.
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+For instance, when your computer is in the laboratory contacting the Moodle server, the packets that carry the information from your computer to the Moodle server contain the source address of the laboratory computer and the destination address of the Moodle server. The source port is web browser and the destination port is the web server that serves Moodle.
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Internet addresses are stored on 4 bytes (32 bits), normally presented to users as strings of 4 decimal values. Each decimal value between 0 and 255 is the decimal representation of one of the 4 bytes: "(0-255).(0-255).(0-255).(0-255)". Examples of IP addresses are: `10.0.1.10`, `192.168.10.11`, `136.145.54.10`.
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@@ -212,3 +212,6 @@ Source_Address Destination_Address Source_Port Destination_Port Octects Packets
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[4] http://intranet.deei.fct.ualg.pt/IC/t22.html
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