Saturday, November 15, 2008

Know Your IP Address and Secure It


Definition :
"An Internet Protocol (IP) address is a numerical identification (logical address) that is assigned to devices participating in a computer network utilizing the Internet Protocol for communication between its nodes". -- SourceWikipedia

The Internet Protocol (IP) has two versions currently in use which are IPv4 and IPv6.
This article represents to IPv4 version only.

In general, an IP address is a 32-bit decimal number that is normally written as four numbers between 1 to 255 (8 bits or 1 byte each), each seperated from the other by a decimal point. This standard is known as "Dotted Decimal Notation".
e.g.- 117.200.77.110

IP addresses are divided into number of ranges/classes as given in the table below-

Class Range
A0.0.0.0 to 126.255.255.255
B128.0.0.0 to 191.255.255.255
C192.0.0.0 to 223.255.255.255
D224.0.0.0 to 239.255.255.255
E240.0.0.0 to 255.255.255.255

e.g.- IP Address 192.168.24.114 belongs to Class 'C'.

How to find out IP Address of your system ?
1) Connect to the Internet.
2) Launch MS-DOS Command Prompt.
3) Type "netstat -n", Press Enter.

You will get the output similar to following-


The IP Address shown in local address field denotes IP Address of your system.
In this case it is 117.200.160.151

IP Address Formats :-
Four different formats of IP Address along with example is as given below-

1) Domain Name System (DNS) : www.computersecuritywithethicalhacking.blogspot.com
2) Dotted Decimal Format : 72.14.203.191

Converting DNS IP Address into Normal IP Address :-
You can easily get the IP Address of any domain by various methods such as WHOIS, Netstat, Ping, Traceroute, etc.
Here I have used 'Ping' to get IP Address.

1) Connect to the Internet.
2) Launch MS-DOS Command Prompt.
3) Type "ping domainname", Press Enter.

You will get the output similar to following-



Here, IP Address for Domain "www.computersecuritywithethicalhacking.blogspot.com" is "72.14.203.191"

Thus by typing "http://computersecuritywithethicalhacking.blogspot.com/" OR "72.14.203.191" in your browser will take you to the same site.

Not all of these formats work in all browsers.

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