How to Check Your IP Address

Well, you are using Internet and wish to know your Public IP Address that currently used for you Internet connection. This is specially if you are using dial up connection or using a proxy server to connection to the Internet then ipconfig on windows or ifconfig on linux machine does not show your Public IP Address rather they show your Private IP address like below.

E:\>ipconfig

Windows IP Configuration


Ethernet adapter Local Area Connection:

        Media State . . . . . . . . . . . : Media disconnected

Ethernet adapter Wireless Network Connection:

        Media State . . . . . . . . . . . : Media disconnected

PPP adapter GP-INTERNET:

        Connection-specific DNS Suffix  . :
        IP Address. . . . . . . . . . . . : 10.130.20.120
        Subnet Mask . . . . . . . . . . . : 255.255.255.255
        Default Gateway . . . . . . . . . : 10.130.20.120

If you are not aware about Private and Public IP address then a little discussion about IP Address will help you to understand the thins.

Internet Protocol (IP) Address is a numerical label that is assigned to a device in order to uniquely identify in a network/Internet. In the Internet Protocol Version 4 (IPV4) the designers of TCP/IP defined an IP address as a 32-bit number which limits the address space to 4,294,967,296 (2 to the power 32) possible unique addresses. Out of 4,294,967,296 IP Addresses some addresses are reserved such as private networks (~18 million addresses) or multicast addresses (~270 million addresses).

The addresses which are reserved for private networks are called Private IP Address and rest addresses are called Public IP Address. Following is the range of all IP Address exists in IPV4.

Class	First octet in binary	Range of first octet	Network ID	Host ID	Number of networks	Number of addresses
A	0XXXXXXX	0 - 127	a	b.c.d	27-2 = 126	224-2 = 16,777,214
B	10XXXXXX	128 - 191	a.b	c.d	214 = 16,384	216-2 = 65,534
C	110XXXXX	192 - 223	a.b.c	d	221-1 = 2,097,151	28-2 = 254

From the above list following is the range of Private IP Address,

Class	Start	End	No. of addresses
24-bit Block (/8 prefix, 1 x A)	10.0.0.0	10.255.255.255	16,777,216
20-bit Block (/12 prefix, 16 x B)	172.16.0.0	172.31.255.255	1,048,576
16-bit Block (/16 prefix, 256 x C)	192.168.0.0	192.168.255.255	65,536

So, 10.130.20.120 is my private IP Address and as Private IP addresses are not routed on the Internet and thus their use need not be coordinated with an IP address registry so to communicate with Internet there must have a Public IP address. There are many websites through which you can check your IP Address along with many features. From them, I see AnalyzeMy really helps me which much more information.