IP Address Explained
Added 3th Nov 2008 - Viewed 320 times
IP Address is a concept similar to what your postal code is, some
people call the IP your "eHouse Number". IP is like the numerical ID of
your computer using which uniquely identify your computer and it's the
others hold of you on a network or the internet.
When the early internet age started there was a need felt of an address
that can identified across the global by means of which all the
computers in this world would be able to communicate. But in that age
computers were not a things every household had so it was pretty
obvious that the guys who made the "Intercommunication Standards" or
the IEEE did not anticipated that the internet would grow at this pace
and we ever run of addresses, which we actually are! Scientist have
estimated that all the IPs of the current version - IP version 4 (IPv4)
will be exhausted by the year 2010
Another thing people quite confuse IP for is that, nearly 99% of times
they take it for just an address which it is not. IP is not just a
number or an address it's a protocol - The Internet Protocol (IP). It
is part of the TCP/IP protocol stack which has many more protocols that
are now the standard of inter-communication on networks.
Let's assume a scenario:
Bob wants to send a letter to Sally.
What bob needs is:
1)An House Number
2)A street name/number
3)And a correct Pin Code
So Sally's address might look like this:
56 - B Some Street Some Area City Country Pin - 110024
Now we all know that the house numbers are unique to every house and if
Bob gets it wrong the letter might never reach to Sally. Similarly IP
addresses are the house computers for the computer!
Whenever two computers are intercommunicating, sending packets they
need an IP address to know where the computer actually is. So it's the
IP Address that identifies your computer on a network and lets you
communicate around.
(Though locally its not just the IP Address that is needed. Another
address called the physical address or the MAC address that is needed.)
IP Address - How does it look ?
Something like this: 64.233.187.99
Try opening this IP address in your browser (Internet
Explorer/Mozilla/etc) and you will find that this takes you
to - Google !
(How it reaches to google is a out of scope of this article)
An IP is address is a 32 Bit (4 Byte) long address which has 4 octets
which always look something like:
XXX.XXX.XXX.XXX
The largest possible value of each octet is 255 ie the last IP is
255.255.255.255.
Some Examples of IP Addresses: 192.145.1.12, 10.0.0.2, 12.125.69.24 and
so on.
(we are dealing with IPv4 in this section)
Subparts of an IP address:
An IP Address can be divided into two parts
1)Network Part
2)Host Part
A network part of an IP identifies the NETWORK ADDRESS where as HOST
part is address of each device that's hooked up to the network.
IP address are also classified under 3 usable categories/classes-
1)Class A : 1-127.X.X.X
2)Class B : 128-191.X.X.X
3)Class C : 192-223.X.X.X
So
Class A - Starts from : 1.0.0.0 and ends at 127.255.255.255
Class B - Starts from : 128.0.0.0 and ends at 191.255.255.255
Class C - Starts from : 192.0.0.0 and ends at 223.255.255.255
The MATHS in IP Addressing:
I know this quite sounds boring but to truly understand IP addresses we
really need to know some simple Math's that's involved in IP addresses.
Computers till date work only on a number system called the BINARY
NUMBER system. In binary number system there are only two values '1 and
0' or also called 'ON and OFF' ! Why? Because computers are basically
electronic devices, so either there is a current or no current in the
circuits, ie either it is ON or it OFF!
As said before IP an 32 bit address, so to a computer an IP address
looks something like this:
11100011.00011101.11011011.01011010
Weird huh?
So how many total number of IP are there? Well my logic says something
like - 232
That will look like - 4,294,967,29
Unique addresses, but there not all can be used which is explained
later.
So lets understand IP CLASSES in terms of bits. The first 3 bits of the
most significant octet of an in IP Address is the NETWORK address. So
the classed looks like this-
Class A: 0XXXXXXX.xxxxxxxx.xxxxxxxx.xxxxxxxx
Class B: 10XXXXXX.xxxxxxxx.xxxxxxxx.xxxxxxxx
Class C: 110XXXXX.xxxxxxxx.xxxxxxxx.xxxxxxxx
The importance of bits and this binary logic involved is important to
understand the concept of Subnetting.
Why do we need a "Network Address" and a "Host Address" ?
Lets try and understand this by taking an example of an office
building. A general office building as many departments like -
Management, Administration, Human Resource, R'n'D, Helpdesk etc, etc.
Now let's assume our office building is a multistoried large building
with each floor dedicated to some department or the other and each one
having its own resources like a printer, a file server and a shared
internet connection for all of them!
Suppose floor 1 is the administration department, having a dedicated
database server and floor 6 has the HR department with its own server.
In such a scenario the HR department directly concerned with the Admin.
Department so they would not really be interested in having to share
any of their resources!
So here is where the network address comes to play. A Network address
of IP address makes a kind of boundary which local devices cannot cross
themselves! So as per our example there would be various networks in
our office which keeps the computers of one network away from the other.
The computers in the HR department might IP Address like this-
192.168.10.56 and that in the Admin. Department might have something
like - 192.168.8.24
So if you have guessed it,
in the IP Address, 192.168.10.56
192.168.10 is the network address and
.56 the host address.
And similarly in 192.168.8.24
192.168.8 is the network address and
.24 the host address
The host address can be assigned to all the devices on the network like
computers, printers etc.
The Reserved IPs
The creators of IP address have reserved many IP addresses for some
purpose.
The very first IP ie 0.0.0.0 (all bits turned 0) and the very last IP
255.255.255.255 cannot be used as they have a purpose called the
broadcast for which they are reserved.
Also there are something called as PRIVATE IP ADDRESSES that anyone can
use .
Anyone? So what are the other IPs ?
Public IPs
An PUBLIC IP ADDRESSES is sometimes called the most valuable asset in
the online world! That is a public IP address is like your house number
online! It is the unique address which is give to your computer when it
goes online. The public IPs cannot be used on local networks (LANs) and
have to be bought from the Network Information Center or the NIC
Private IPs
So if I would like to setup a local network of two of my computer would
I have to buy IPs? NO! THANKFULLY! There is something called the
Private IPs that anyone can use for their local networks and they range
from :
From 10.0.0.0 to 10.255.255.255 (Class A)
From 172.16.0.0 to 172.31.255.255 (Class B)
From 192.168.0.0 to 192.168.255.255 (Class C)
Private IPs cannot communicate on the internet, they are meant to be
used on local networks and not for the internet. Whereas Public ips are
UNIQUELY meant for usage ONLINE that is all the IPs other than range of
above are UNIQUE to some organization for the other. As a small piece
of advice I suggest that remember these ranges!
Something you can try is goto: http://www.secretipaddress.com/
And you will see that your PUBLIC IP is displayed.
Someother reserved IPs
1)127.X.X.X is another reserved address and is used for testing, often
called the LOOPBACK.
2)Class D IP addresses 224-239
3)Class E 240-254 are also reserved.
A lil' outlook to the Future- IPv6
IPv6 is the upcoming version of the IP protocol which is suppose to be
fully implemented by the year 2010. The necessity of this new version
is due to rapid exhaustion of IPv4 addressed. The major change in this
address is that instead of a 32 Bit address it is now a 128 bit long
Hexadecimal address!
128 Bits will mean that there will 2128 addresses! WOHoo! An estimate
suggest that even if every square inch of this milky way is given IP
addresses, still they will not be exhausted!
Example of an IPv6 Address :
2871:ab11:0:1724:0:567:1:1