Internet Notes

IP and DNS

Binary Numbers

  • Computers use binary (or base 2)
  • Humans use decimal (or base 10)
Dotted Notation
  • each section is an Octet
  • The computer converts it all into a big number
  • (conversion activity, what is Pineview's number?) - 3429971970

Network Address Classes

  • Dotted notation allows for organization into classes
  • Net / Host

Address Classes

  • Class A: 1st Octet -
  • Class B: 1st and 2nd Octet -
  • Class C: 1st, 2nd, and 3rd Octet -

Search activity

What are all the Class A networks? (126 possible)

CLIENTS, SERVERS, PORTS, and PROTOCOLS.......don't for get security?

Clients and Servers

All of the machines on the Internet are either Servers or Clients.

  • Server: The machines that provide services to other machines.
  • Clients: The machines that are used to connect to those services are clients.


  • Web Servers - Host website and website files.
  • Multimedia Servers - holds media files - Video and audio.
  • Realtime Communication Servers - Chat, IRC, Instant Messaging and video.
  • FTP Servers - Used to transfer files from one computer to another.
  • Mail Servers - Used to send and receive files and messages.

Server Address
  • IP addresses for a server usually says the same for a long time (static IP).

  • Any machine can be a Client.
  • Any User Machine Can Be a Server.
  • Sometimes software is the server.
  • Sometimes a computer is both a client and a Server.

  • A Server that makes services available using numbered ports (different port or number for each service on the server).
  • Web (HTTP): port 80 (typically)
  • FTP: port 21
  • SMTP: port 25
  • HTTPS: port 443
Clients connect to a service at a specific IP address and on a specific port number.

Virtual ports are part of TCP/IP networking.

These ports allow software applications to share hardware resources without interfering with each other.

Computers and routers automatically manage network traffic traveling via their virtual ports.

Network firewalls additionally provide some control over the flow of traffic on each virtual port for security purposes.

HTTP (Hypertext Transfer Protocol)

The rules on how people or Clients and Servers talk to each other.