Valid IP Addressing vs Invalid IP Addressing

IP Addressing: –

IP addressing in network area we consider as a unique string of numbers separated by full stops that identifies each computer using the Internet Protocol to communicate over a network. It is very useful in internet, when we want to share information with each other. It is used by many people in their networks but sometimes it is difficult to identify the addresses which either reserved or already used for broadcast etc. This times, We bring you some important ip addresses which should be known by the person who want to go for CCNA or pursue career in network field.

1) When all the net id as well as host id portion bits of an IP address are zero then the address reserve for default routing. It is invalid IP address.

For e.g.: –              0       .       0      .       0       .       0

00000000.00000000.00000000.00000000

Net id                    Host id

2) When all the host id  portion bits of an IP address are zero then it represent the Network address. It also invalid IP address.

Class A            1       .       0       .       0      .       0

00000001.00000000.00000000.00000000

Net id                      Host id

10      .       0      .       0       .      0

00001010.00000000.00000000.00000000

Net id                     Host id

Class B           128    .       0       .       0       .      0

10000000.00000000.00000000.00000000

Net id                      Host id

172    .       0       .      0       .      0

10101100.00000000.00000000.00000000

Net id                      Host id

Class C             192    .       0      .        0      .      0

11000000.00000000.00000000.00000000

Net id                     Host id

3) When all the host id portion bits are one then it represent the Broadcast address. It is also invalid IP address.

For e.g.: –

Class A               1       .      255   .       255   .    255

00000001.11111111.11111111.11111111

Net id                      Host id

Class B              128    .      255    .      255    .   255

10000000.11111111.11111111.11111111

Net id                      Host id

Class C                 192.       168    .        1      .    255

11000000.10101000.00000001.11111111

4) Loopback or self-testing address: – It is use for self-testing of LAN card. It is use for test TCP/IP setting.

For Example.    127.0.0.0   to 127.255.255.255

The IP Address 127.0.0.1 is also known as Localhost for Internal Server Server .

5) APIPA (Automatic Private Internet Protocol Address)

It is stand and generated by client PC automatically. When DHCP server is not available or DHCP server is busy in a network. These IP address are used to stop the unusual broadcasting. Communication is possible but only within LAN. APIPA is valid IP address.

For Example.      169.254.0.0 to 169.254.255.255

6) Private IP Address

•    It is also called non routable address.
•    Internet is doesn’t run on private IP address.
•    It is free of cost. It is not use in WAN network.
•    Use to avoid the wastage of public IP address.

1.       10.0.0.0       to    10.255.255.255
2.       172.16.0.0   to    172.31.255.255
3.       192.168.0.0 to    192.168.255.255