Accessing equipment in LAN thru Internet - Part 2

Welcome to the second part of the tutorial. Here we will learn a bit about what IP addresses are and why are they important to us.

If you have enough knowledge on that topic, just skip to the next tutorial.

If you are anything like my wife you hate numbers. And I am not here to scare you away. So I will keep this as basic as possible but still impart enough to understand and troubleshoot.

Nowadays we have mobiles. Each mobile has a number. So you ring the mobile number and you reach that mobile.

When it comes to computers, it is the same. Each computer has a number. When you ping it, you reach it. This number is called the IP address. You don't need an IP address to run a computer. You need it only if you are going to be in a network.

Anatomy of an IP address

IP address consists of 4 parts. Each part is separated by a dot. Each part has a value between 0-255. No negative values. No decimals. And it cannot be more than 255.

Sample IP address 122.321.32.1 See it is very much like my tel no. +1.555.213.5555
And it really kind of apes the telephone number. Country code.company code. area code. local extension

NOTE: The current IP addresses are IPV4 convention. If you read IPV6. Just ignore it for now. It is not important for this tutorial.

Two types of IP

This is the las bit you need to about IP address - promise.

You know how in big companies you call a number and it says, please dial an extension to reach the person you want. You have the telephone number and the extension - two parts. The telephone number is available to all - so we can call it the public number.
The extension of the CEO though may not be known - so we can call it private.

It is no different for the IP's. There are public IP's and there are private IP.

Every instrument that connects to the INTERNET WAN has a individual ip address. There are NO two computers in the internet having the same number at the same time.

Business normally buy a static public ip address. Just like a permanent telephone line.

People using internet over cable/dsl always have to connect (dial-in). When they connect, they are allotted a public IP from a pool and this stays with them as long as they are connected. Upon disconnect the number is returned to the pool of the ISP. When you connect again, you will be allocated a number again. It may or may not be the same. Such temporary public ip are called dynamic IP.

ISP is your Internet Service Provider - the company providing you the internet.

When you connect you computer in your own private network, you give it a private ip address. The private IP addresses have to be one of the following:

FROM        TO
10.0.0.0        10.255.255.255
172.16.0.0    172.31.255.255
192.168.0.0  192.168.255.255

The above IP addresses can be duplicated. In fact you computer may have the same private IP address as mine !!!

Let us summarize:

- IP addresses are the network address of a computer.
- Computers, or equipment like modem, router. in the Internet have Public IP Address
- Computers, or equipment like laptop, printers etc., in your home network have a private IP Address.
- Both public and private IP address are similar in construction. The only difference is that private IP addresses belong to a range that has been marked private.

THAT IS IT. You really need to understand this part to go further. Read and read it if required.

We are off  to the good stuff - Yipee... Onwards my friends to the next part.