classful subnet tableHere's the classful subnet table

What is a classful IPv4 address?
The definitions of what this is will be included below. This will include the zero subnet or as many people in the industry will call it ‘subnet-zero.’
These definitions will also be using a CIDR notation.

Directly below areĀ unicast address space – this is the most important addressing used.

Class A 1.0.0.0/8 – 126.0.0.0/8
Class B 128.0.0.0/16 – 191.255.0.0/16
Class C 192.0.0.0/24 – 223.255.255.0/24

Now this is multicast address space – typically, this is not as important until we start using VOIP and Video applications within our network.

Class D 224.0.0.0 – 239.255.255.255
Class E 240.0.0.0 – 255.255.255.255

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