Intro to Basic Networking (Part I):

Each computer connected to a network has an IP Address

  • IP (Internet Protocol) address
  • Numerical address that identify your computer on the network

Subnet Mask (netmask) address:

  • This address provides a more accurate description of the network the computer is attached too
  • A subnet mask is used to tell the network devices (whether it be the computer or any routers, modems, etc.) what addresses are local (belongs to this network), and what addresses are remote (belongs to that network).
  • So, if a computer's IP address is 192.168.1.104, and its subnet mask is 255.255.255.0, then the computer (and every other device attached to the same network) will assume that every IP on that computer's local network will be in the format 192.168.1.xxx, with xxx being the only part that would vary. Likewise, if the subnet mask is 255.255.0.0, then the computer will assume that every IP address in its local network will be in the format of 192.168.xxx.xxx.

What makes up a network?

These are the bases of a computer on a stand-alone network

  • stand-alone network:
  • A desktop or laptop computer that is used on its own without requiring a connection to a local area network (LAN) or wide area network (WAN).
  • Although it may be connected to a network, it is still a stand-alone PC as long as the network connection is not mandatory for its general use.

If a device wanted to communicate with another network, such as the internet it would need a few more settings

  • In order for a device to communicate with another network, it would need a Gateway to talk too
  • A Gateway address:
  • It’s the same as the IP Address of a device on the network, that device usually being a router, is responsible for communications between hosts of other networks
  • For example, if your computer is requesting an internet webpage, the request first runs through your default gateway before exiting the local networkto reach the internet.

  • DNS (domain name services) server address
  • Used to transfer website names to IP address
  • These are large systems on the internet that can obtain a database of sorts that has a listing of domain names and their associated IP Addresses

Once all these pieces are in place, your system can connect to another network, like the Internet

To make these concepts a little bit clearer, see the pic of a LAN (local area network)

The room itself is in-closed in a wall, known as the subnet mask

  • This subnet mask identifies any systems within this room as belonging to this network
  • Local network traffic stays within the subnet
  • Any traffic not bound for or destined for another system within this room, has to go thru the doorway or gateway before entering other networks to find it’s next destination
  • For example… if a system within the subnet room needs to request a website, that traffic has to leave the subnet room to locate that website
  • 1st, the computer needs to find out what IP Address houses the website that they wish to access
  • So they will ask DNS to find this out for them
  • Once they get the IP address of where they want to go, the computer sends it’s request for the website out of the subnet
  • The traffic encounters the door to the room, which is the network gateway and ask the gateway where it needs to go to find this website
  • The gateway then adds information to the data request such as a map thru the hallway that should route it to the appropriate room that has the website
  • The website responds to the original request, sending a response back to the original requesting computer via the routing information found in the request

Hardware:

Every computer has an IP Address assigned to them

  • There are 2 other addresses a network computer has
  • Local (loopback) IP address: 127.0.0.1
  • Not assessible from other machines
  • Meant to be used on a per machine basis to test to see if IP protocols are working on a system
  • MAC address: 00:09:6B:CD:2B:87
  • The actual hardware address that’s burnt into the network interface adapter
  • Designed to uniquely identify each piece of hardware on any network

Routers:

  • Direct network traffic to there destinations
  • Routers keep their own listing of IP Addresses of where they should send data
  • For example, when you’re at home and you’re on your computer that’s connected to the internet, you’re using a router that communicates with your internet service provider
  • This device (see below) takes the traffic that’s bound for the internet and routes it to your internet service provider
  • Your service provider will then check their collection of routes, known as the routing table to send your data request on their way