I know.
I know what you're thinking.
You're really chomping at the bit to get to subnetting.
But before we talk about it, it's better to learn the IP classes and the subnet masks first, right?
Octets of the IP address are broken down to provide an addressing scheme that can accommodate large
and small networks.
So there are basically five different classes of networks, and they range from A to E.
We're going to focus on classes A, B and C, which provide unicast addresses for networks of three
different network sizes.
Class D is for multicast networking and the Class C address range is reserved for future or experimental
purposes.
So given an IP address, its class can be determined from the three high order bits.
And by that I mean the three leftmost bits in the first octet.
In a class A address.
The first octet is a network portion.
So Class A has a major network address of 1.0.0.0 all the way through.
127.255.255.255.
The next 24 bits are for the network manager to divide into subnets and hosts as he or she sees fit.
Class A addresses are used for networks that are more than 65,536 hosts.
In a Class B address.
The first two octets are the network portion.
So class B has a major network address of 128.0.0.0 all the way through.
191.255.255.255.
Octets three and four.
That means 16 bits are for local subnets and hosts.
Class B addresses are used for networks that have between 256 and 65,534 hosts.
And finally, in a Class C address, the first three octets are the network portion.
Class C has a major network address of 192.0.0.0 all the way through to 23.255.255.255.
Octet for eight bits is for local subnets and hosts.
Perfect for networks with less than 254 hosts.