IP address ending by 0 = IP Network Address?

December 2016

IP address ending by 0 = IP Network Address?



Myth


IP address ending by 0 = IP Network Address?

It is a popular belief that all IP addresses ending with 0 being the network address.

Reality


False: I will not go into detail on how to identify a network address or host address. But here's an example of IP type xxx0 that will perfectly fit for a host:

If I take the example of the network 10.0.0.0/23 or 255.255.254.0 in this case certainly is a 10.0.0.0 network address but not 10.0.1.0.

Explanations


10.0.0.0 in binary becomes
0000 1010.0000 0000 .0000 0000.0000 0000

and 255.255.254.0 in binary becomes
1111 1111.1111 1111 .1111 1110.0000 0000

So the valid host IP addresses are:
0000 1010.0000 0000.0000 0000.0000 0001 à 0000 1010.0000 0000.0000 0001.1111 1110
or

10.0.0.1 à 10.0.1.254 (10.0.1.255 then the broadcast address)

Then the next host IP address is valid:
0000 1010.0000 0000.0000 0001.0000 0000
or
10.0.1.0

Thanks to Nitch for this tip

Related :

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