What is the difference between classless and classful ip address? And please give an example, to differnciate them, thanks

Your default class addresses are Class A 0-127, Class B - 128-191 Class C - 192-223 for the 1st octet values

Classful ip addresses are ip addresses that follow this standard subnet ranges for class A, B, C so a classful router protocol like ripv1 will always assume that the address 172.16.1.2 has a subnet mask of 255.255.0.0 even if you want it to have a subnet of 255.255.255.0 so on a classful router protocol 172.16.1.2 will always have the range 172.16.0.0 - 172.16.255.255 (because the value 172 in the 1st octet falls in the Class B range of 128-191 and class B addresses have the subnet mask set to 255.255.0.0)

Classless ip addresses mean that the address range is determined by the subnet mask and hence the same address 172.16.1.2 255.255.255.0 will now be looked at as having its range as 172.16.1.0 - 255 because 255.255.255.0 corresponds to that range. P.S. Rip was updated to support this (ripv2)

yes, that is right.In classful ip predefined format only we can use for example

/8,/16,/24 like this.it is limited.
but classless ip has we define as per our network
example


in a network if we want to assign only 2 ip the CIDR value is /30.if you need 14 addresses use /28.like this we can change our network.

What is the difference between classless and classful ip address?

Classful Ip address:

Classful Ip address is take only the pre-defined bits in Network ID (8,16,24) in addressing. Example. Class A pre-defined bits - 8 10.2.1.10 /8, Class B Pre-defined bits -16 172.16.1.20 / 16, Class C Pre-defined Bits -24 192.168.1.30 /24 This type of address is called Classful Ip address.

Classless Ip

Classless Ip address is assign any number of bits in network ID is called Classless IP address. Example 10.2.1.10 /12. Bits barrow from Host Id added in to Network id. This called Classless Ip address.

K.C.Suresh Babu
Network Administrator.

Classfull IP Address:

the Default mask of Classes are called Classful ,Example:
Class A= 255.0.0.0 , Classs B: 255.255.0.0 Class C= 255.255.255.0


Classless IP adress:

Defined by System Administrator. Ite means used From IP Sub netting

Example: Class A: IP 10.0.0.0 /9 => sub net = 255.128.0.0
Class B: Ip 172.0.0.0 /18 => Sub net => 255.255.192.0
Class C: IP 192.0.0.0/ 27 =>sub net => 255.255.255.224

Nasir Ayubi KBL Afghanistan
IT . Trainer

I will simply explain this topic
when we use a default subnet mask tat means
ex: class c : 192.168.0.3
default subnet: 255.255.255.0
This is called classfull address
when we use a variable subnet mask means classless address
ex: class c:192.168.0.3/24

The difference between classful IP addressing and classless IP addressing is in selecting the number of bits used for the network ID portion of an IP address. In classful IP addressing, the network ID portion can take only the predefined number of bits 8, 16, or 24. In classless addressing, any number of bits can be assigned to the network ID.