In a classful addressing the IP address with 0(zero) as network number:
2015
In a classful addressing the IP address with 0(zero) as network number:
- A.
refers to the current network
- B.
refers to broadcast on the local network
- C.
refers to the broadcast on a distant network
- D.
refers to loopback testing
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Correct answer: A
Answer: An IP address whose network portion is all zeros refers to the current (local) network in classful addressing.
Key points:
This-network convention: A network field of all zeros is interpreted as "this network" (the local network).
Broadcast addresses: Broadcasts are indicated by setting the host portion to all ones (for example, 192.168.1.255 for a /24). A zero network number does not mean broadcast.
Directed (distant) broadcasts use a specific network number with all host bits set to one; they are not signified by an all-zero network field.
Loopback: Loopback addresses are in the 127.0.0.0/8 block (commonly 127.0.0.1), unrelated to the all-zero network convention.
Historical note: Early classful IPv4 specifications used the all-zero network convention. Modern practice prefers explicit network numbering to avoid ambiguity.