Of the above two types, the most widely used is the 4th version, IPv4 version. However, the 6th version, IPv6, is currently being used for computer networks around the world
IPv4 version IP addresses consisting of 32 bits are dot-decimal notation. These 32 bits are divided into four 8-bit segments called octets.
Each IP address has two main sections. They are,
Partition with Network ID (NetwoAn IP address or Internet Protocol address is a numeric label used to identify different devices (printers, laptops, routers, switches, etc.) used in a computer network.
There are currently two types of IP addresses used:
IPv4
IPv6rk Address Portion).
Part with Host ID (Host Address Portion).
The part with the network address identifies the relevant computer network and the part with the host address identifies the endpoints such as printers, laptops, routers, switches etc ... in the relevant computer network.
Understand Network ID and Host ID.
Suppose there are 10 houses with addresses 1,2,3,4,5,6,7,8,9,10 on either side of Road A. The road to the 10 houses is the same, but the addresses of each house are different. If you want to deliver a letter to the house with address 8, you have to go to road A and hand over the letter to house number 8. The same thing happens with a computer network. The network ID of a computer network is the same as the path A in the example. Also the Host ID is the same as the addresses of 10 houses 1,2,3,4,5,6,7,8,9 or 10 in the example.
The Network ID of the IP address of a computer network does not change and the Host ID always changes.
Thus all the IP addresses we use are divided into 5 classes according to an international standard. This is called Address Classes / Classful Networks and has been in use since 1981 before the concept of CIDR or Classless Inter-Domain Routing was introduced in 1993.
The 5 classes in which IP addresses are shared are:
Class A
Class B
Class C
Class D
Class E
Class A, Class B and Class C are for general unicast addresses while Class D is for multicast addresses. The final class, Class E, is reserved for future use or for experimental purposes.
These IP addresses are assigned to classes by the Internet Assigned Numbers Authority (IANA).
Class A IP addresses
The first bit of the first octave of these IP addresses is always set to 0.
Therefore, the first octave of Class A IP addresses ranges from 0 to 127.
However, since addresses starting with 127 are reserved for the loopback address and addresses starting with 0 are reserved for the default network, addresses beginning with those values cannot be used in normal use. For example, you cannot configure a static IP address on a computer as 127.0.0.1. Also, an IP address such as 0.1.1.1 cannot be configured as a static IP address on a computer.
For this reason, the IP addresses for Class A range from 1 to 126.
The first 8 bits or the first octet of the Class A IP addresses indicate the Network ID and the last 24 bits indicate the Host ID.
Class B related IP addresses
The first and second bits of the first octave of these IP addresses are always set to 1 and 0, respectively.
Therefore, the first octave of Class B IP addresses ranges from 128 to 191.
Class C IP addresses
The first three bits of the first octave of these IP addresses are always set to 110.
Therefore, the first octave of Class C IP addresses ranges from 192 to 223.
The first 24 bits or the first three octets of Class C IP addresses indicate the Network ID and the last 8 bits indicate the Host ID.
Class D related IP addresses
The first four bits of the first octave of these IP addresses are always set to 1110.
Therefore, the first octets of IP addresses for Class D range from 224 to 239.
Class E IP addresses
These IP addresses are reserved for research purposes. The first four bits of the first octave of these IP addresses are always set to 1111.
Therefore, the first octave of Class E IP addresses ranges from 240 to 254.
In summary
Classes related to personal IP addresses
According to RFC1918, private IP addresses are non-routable IP addresses. These are blocked by Internet service providers and therefore those addresses cannot be used for data transfer over the Internet.
IANA allocates the following three IP spaces to private IP addresses.
