Internet 101

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IP and DNS

IP = Internet Protocol
iPv4: xxx4 (numbers)
iPv6: xxxx6 (numbers and char)
DNS = Domain Name System
Hackers do DNS Spoofing user ask DNS about the IP of a website (e.g. http://google.com)
then user turn to Internet Service Provider(ISP) to get the content

How are data transmitted perfectly?

  1. data are divided in to Packets
  2. Packets are transimitted in the CHEAPEST way through Routers and reassembled at destination
  3. TCP(Transmission Control Prortocal) is to ensure the integrity of the data.

How people browse a webpage?

  1. PC uses URL(Uniform Resourse Locator) to connect the server sends request to server in HTTP(HyperText Transmission Protocol)
  2. Server sends back the HTML(HyperText Markup Language) which contains the context of the webpage
  3. PC requests additional data(images,videos etc) that included in HTML
  4. Cookies are used to remember user information
  5. SSL(Secure Socket Layer) and TSL(Transport Layer Security) are used to protect the transmission, or HTTPS(S for security).
  6. Servers need digital certificate to establish secured connection.

Cybersecurity

Public Key for Encryption
and Private Key for Decryption

Hackers’ methods:

1 Virus
2 DDOS(Distributed Denial-of-Service) Useless info makes server go haywire
3 Phishing(Sounds like Fishing) scam