Fourth octet is the address and the first three octets are the address

Career Paths IT and Cybersecurity Foundations
1

can anyone help me to otherstand about fourth octect and three octect ,from this address 192.168.10.100 , i still not understand for that

Thank you

2

IPv4 addresses are made up of four “octets”:
1.2.3.4

Now depending on the network mask, octets 1-3 are used to indicate the “network”, and any remaining are used for the “host”.

So, assuming 192.168.10.100 / 24 (meaning octets 1-3 are network and octet 4 is the host) this is host 100 on the 192.168.10.0/24 network.

The reason they are called “octets” is because each number is in reality 8 bits:
00000000 with each bit having meaning:

128 64 32 16 8 4 2 1

So for example the first octet, 192 is 11000000 (128 + 64 + 0 + 0 + 0 +0 + 0 + 0)

3

Dear Joseph
Thank you for the explanation, now I understand better