03 August, 2011
IP ADDRESSING
An IP address is a 32 bit numeric identifier assigned to each machine on an IP network. It designates the specific location of a device on the network. An IP address is a software address and designed to allow host on one network to communicate with a host on a different network regardless of the type of LANs the hosts are participating in.
IP TERMINOLOGIES
Bit: A bit is one digit, either a 1 or a 0.
Byte: A byte is 7 or
8 bits, depending on whether parity is used.
Octet: An octet, made up of 8 bits is just an ordinary 8 bit binary number. In most cases byte and octet are completely interchangeable.
5 classes;
Class A: Class A IP address structure.
NNNNNNNN: HHHHHHHH: HHHHHHHH: HHHHHHHH
N-network
H-Host
subnetMask:255.0.0.0
Value of the first bytes: 1 to 126
No of the network: 126No of the Host: (256*256*256)-2=16,777,216-2=16,777,214
Because two hosts we are not using so we reduce 2.
X.0.0.0 and
x.255.255.255
Purpose: we can use class A with large network with many devices because it contains too many host on the same network 16,777,214-host.
Class B: Class B IP address structure
NNNNNNNN: NNNNNNNN: HHHHHHHH: HHHHHHHH
N-network
H-Host
subnetMask:255.255.0.0
Value of the first bytes: 128-191
No of the network: (191-127)*256=16,384
No of the Host: (256*256)-2=65,536-2=65,534
Purpose: we can use class B with Medium network with many devices because it contains host on the same network 65,534-host.
Class C: Class C IP address structure.
NNNNNNNN: NNNNNNNN: NNNNNNNN: HHHHHHHH
N-network
H-Host
subnetMask:255.255.255.0
Value of the first bytes: 223-192
No of the network: (223-191)*256*256=2,097,152
No of the Host: (256)-2=254
Purpose: we can use class c with small network because it contains very low no of host on the same network 254-host.
Class D:
Range:224-239
Purpose: it is used for multicasting
Class E:
Range: 240-254
Purpose: now it is not using .Reserved for Future use.
A public IP address is assigned to every computer that connects to the Internet where each IP is unique. Hence there cannot exist two computers with the same public IP address all over the Internet. This addressing scheme makes it possible for the computers to “find each other” online and exchange information. User has no control over the IP address (public) that is assigned to the computer. The public IP address is assigned to the computer by the Internet Service Provider as soon as the computer is connected to the Internet gateway.
A public IP address can be either static or dynamic. A static public IP address does not change and is used primarily for hosting webpages or services on the Internet. On the other hand a dynamic public IP address is chosen from a pool of available addresses and changes each time one connects to the Internet. Most Internet users will only have a dynamic IP assigned to their computer which goes off when the computer is disconnected from the Internet. Thus when it is re-connected it gets a new IP.
You can check your public IP address by visiting www.whatismyip.com
An IP address is considered private if the IP number falls within one of the IP address ranges reserved for private networks such as a Local Area Network (LAN). The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IP address space for private networks (local networks):
---------------------------------------------------------------------
10.0.0.0 – 10.255.255.255 (Total Addresses: 16,777,216)
172.16.0.0 – 172.31.255.255 (Total Addresses: 1,048,576)
192.168.0.0 – 192.168.255.255 (Total Addresses: 65,536)
----------------------------------------------------------------------
Private IP addresses are used for numbering the computers in a private network including home, school and business LANs in airports and hotels which makes it possible for the computers in the network to communicate with each other. Say for example, if a network X consists of 10 computers each of them can be given an IP starting from 192.168.1.1 to 192.168.1.10. Unlike the public IP, the administrator of the private network is free to assign an IP address of his own choice (provided the IP number falls in the private IP address range as mentioned above).
Devices with private IP addresses cannot connect directly to the Internet. Likewise, computers outside the local network cannot connect directly to a device with a private IP. It is possible to interconnect two private networks with the help of a router or a similar device that supports Network Address Translation.
If the private network is connected to the Internet (through an Internet connection via ISP) then each computer will have a private IP as well as a public IP. Private IP is used for communication within the network where as the public IP is used for communication over the Internet. Most Internet users with a DSL/ADSL connection will have both a private as well as a public IP.
You can know your private IP by typing ipconfig command in the command prompt. The number that you see against “IPV4 Address:” is your private IP which in most cases will be 192.168.1.1 or 192.168.1.2. Unlike the public IP, private IP addresses are always static in nature.
Unlike what most people assume, a private IP is neither the one which is impossible to trace (just like the private telephone number) nor the one reserved for stealth Internet usage. In reality there is no public IP address that is impossible to trace since the protocol itself is designed for transparency.
An IP address is a 32 bit numeric identifier assigned to each machine on an IP network. It designates the specific location of a device on the network. An IP address is a software address and designed to allow host on one network to communicate with a host on a different network regardless of the type of LANs the hosts are participating in.
IP TERMINOLOGIES
Bit: A bit is one digit, either a 1 or a 0.
Byte: A byte is 7 or
8 bits, depending on whether parity is used.
Octet: An octet, made up of 8 bits is just an ordinary 8 bit binary number. In most cases byte and octet are completely interchangeable.
5 classes;
Class A: Class A IP address structure.
NNNNNNNN: HHHHHHHH: HHHHHHHH: HHHHHHHH
N-network
H-Host
subnetMask:255.0.0.0
Value of the first bytes: 1 to 126
No of the network: 126No of the Host: (256*256*256)-2=16,777,216-2=16,777,214
Because two hosts we are not using so we reduce 2.
X.0.0.0 and
x.255.255.255
Purpose: we can use class A with large network with many devices because it contains too many host on the same network 16,777,214-host.
Class B: Class B IP address structure
NNNNNNNN: NNNNNNNN: HHHHHHHH: HHHHHHHH
N-network
H-Host
subnetMask:255.255.0.0
Value of the first bytes: 128-191
No of the network: (191-127)*256=16,384
No of the Host: (256*256)-2=65,536-2=65,534
Purpose: we can use class B with Medium network with many devices because it contains host on the same network 65,534-host.
Class C: Class C IP address structure.
NNNNNNNN: NNNNNNNN: NNNNNNNN: HHHHHHHH
N-network
H-Host
subnetMask:255.255.255.0
Value of the first bytes: 223-192
No of the network: (223-191)*256*256=2,097,152
No of the Host: (256)-2=254
Purpose: we can use class c with small network because it contains very low no of host on the same network 254-host.
Class D:
Range:224-239
Purpose: it is used for multicasting
Class E:
Range: 240-254
Purpose: now it is not using .Reserved for Future use.
What are Public IP Addresses?
A public IP address can be either static or dynamic. A static public IP address does not change and is used primarily for hosting webpages or services on the Internet. On the other hand a dynamic public IP address is chosen from a pool of available addresses and changes each time one connects to the Internet. Most Internet users will only have a dynamic IP assigned to their computer which goes off when the computer is disconnected from the Internet. Thus when it is re-connected it gets a new IP.
You can check your public IP address by visiting www.whatismyip.com
What are Private IP Addresses?
---------------------------------------------------------------------
10.0.0.0 – 10.255.255.255 (Total Addresses: 16,777,216)
172.16.0.0 – 172.31.255.255 (Total Addresses: 1,048,576)
192.168.0.0 – 192.168.255.255 (Total Addresses: 65,536)
----------------------------------------------------------------------
Private IP addresses are used for numbering the computers in a private network including home, school and business LANs in airports and hotels which makes it possible for the computers in the network to communicate with each other. Say for example, if a network X consists of 10 computers each of them can be given an IP starting from 192.168.1.1 to 192.168.1.10. Unlike the public IP, the administrator of the private network is free to assign an IP address of his own choice (provided the IP number falls in the private IP address range as mentioned above).
Devices with private IP addresses cannot connect directly to the Internet. Likewise, computers outside the local network cannot connect directly to a device with a private IP. It is possible to interconnect two private networks with the help of a router or a similar device that supports Network Address Translation.
If the private network is connected to the Internet (through an Internet connection via ISP) then each computer will have a private IP as well as a public IP. Private IP is used for communication within the network where as the public IP is used for communication over the Internet. Most Internet users with a DSL/ADSL connection will have both a private as well as a public IP.
You can know your private IP by typing ipconfig command in the command prompt. The number that you see against “IPV4 Address:” is your private IP which in most cases will be 192.168.1.1 or 192.168.1.2. Unlike the public IP, private IP addresses are always static in nature.
Unlike what most people assume, a private IP is neither the one which is impossible to trace (just like the private telephone number) nor the one reserved for stealth Internet usage. In reality there is no public IP address that is impossible to trace since the protocol itself is designed for transparency.
