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Internet - Coggle Diagram

- - - - IP address
        
        Represented in bits (32)
        
        Divided in parts
        
        DNS
        
        Associates names like webs with the corresponding address
        
        Looks up domain names (www.example.com) and get the associated IP address which is used to connect your computer to the destination of the internet
        
        DNS servers are connected in a distributed hierarchy and divided into zones
        
        Created to an open public communication protocol
        
        DNS spoofing
        
        Hacker taps into a DNS server and changes it to match the domain name with the wrong IP address
        
        Send you to an imposter website
    - - Internet program (IP)
  - - - The design philosophy has allowed the internet to adapt and absorb new communication technologies
- - - - finds a hyperlink and follows it, records the webs information
        
        adds it to search index: a database of information used for doing a search
        
        Search engine looks in each of the words in what you're searching in the search index
        
        gets a list of all the pages on the internet with those words
        
        search engine determines the best matches to show you first
        
        each search engine uses its own algorithm to rank the pages based on what it is you want
        
        1 more item...
- - - - Information on the internet goes from one computer to another in a packet of information
        
        Many kinds of digital information can be sent with IP packets
        
        If you have an image made out of millions of bits, it will brake the image into packets (parts) to transport it easier
        
        Has address of where it came from and where its going
        
        Routers
        
        Keep the packets moving smoothly though the networks.
        
        Keep track of multiple paths to send the packets
        
        Choses cheapest (fastest) available path for each piece of data based on the destination, IP address, for the packet
        
        Having path options makes the network fault tolerant (network can keep sending packets even is there's something wrong)
        
        Reliability
        
        1 more item...
        
        Scalable
        
        Packets are reassembled in order
        
        Packets may arrive at different times and/or out of order
        
        TCP (transmission control protocol)
        
        Manages the sending and receiving all of your data as packets
        
        Does a full acknowledgement and sends back acknowledgements of each packet received. Signs for your delivery if all of the packets are there
        
        Scalable
- - - - longer it is, longer it takes to decrypt it, but doesn't make it impossible
    - - Different keys (private & public) to encrypt and decrypt
        
        Public: anybody can encrypt the message, everybody can see it
        
        Private: can only be decrypted by a computer with access
      - fundation of all secure messaging on the open internet
  - - - Key: a secret password for unlocking a message
- - - - 1= on
        0= off
- - - - Ethernet wire
      - Cheap, signal loss
      - Bandwidth: maximum transmission capacity of a device
        
        Measured in
        
        Bit rate: the number of bits we can send over a given period of time.
        
        Latency: time it takes for a bit to travel from one place to another
    - - Really fast, no signal loss, expensive and hard to work with
    - - Totally mobile, short range
- - - - Billions of devices though thousands of networks (all interconnected)
- - - - What happens?
        
        Computer asks a server for a website (get requests)
        
        Server responds in HTTP
        
        The language used to communicate between web browsers and servers
        
        HTTPS protocols
        
        ensure that your HTTP requests are secure and protected
        
        means your computer is using public key encryption to exchange data securely with the website
        
        Sometimes send information or search
        
        Browser sends information in plain text to webserver using HTTP post request
        
        Can send cookies to browser so websites can remember who you are (ID)
        
        Again in the page, web browser automatically sends it to the server with the requests, sees the ID number and knows who you are
        
        HTML
        
        Language used to tell a web browser how to make a page look (using HTML tags)
        
        Text directly included in the HTML. Images or videos --> separate files with each their own URLs to be requested.
        
        Browser sends separate HTTP requests to server and displays as they arrive.
        
        More image, slower download
- - - - program that's installed usually unintentionally, harms the user and the computer. Can spread.
      - How does it infect?
        
        Fake install
        
        Security backdoor
      - It can steal and delete files, control other programs or allows someone else to control your computer
      - Botnet
        
        digital army by taking millions of computers worldwide to attack or take down websites
        
        DDoS
        
        Hackers overwhelm a website with too many requests
        
        The attack comes from many computers at once
      - Spam email: trick people into sharing sensitive personal information
        
        Phishing scam
        
        Steal information or steal money
      - Hacking --> because of a simple mistake by a human