Hi Rene,
Question- does the subnet mask dictate the class of the network or the value of the octets? It seems here in this example that the subnet mask would dictate whether it was class A, B or C. However I was recently advised that it is not the subnet mask for example it has been recently stated to me:
The class of a network is not determined by its subnet mask. The default subnet mask is determined by the class of a network. The class of a network is determined by the first octet of the IP.
0-127 is considered “class A”.
128-191 is considered “class B”.
192-223 is considered “class C”.
224-239 is considered “class D”.
240-255 is considered “class E”.
So, referring back to my previous example, 171.15.85.0/24 is a “class B” address. The network mask which is used doesn’t matter. What matters is the first octet of the IP. In this case, since we are using a /24 mask, we have “subnetted” the class B address.
I am looking for your insight on this. Thank you for your thoughts.