Networking · Flashcard
How many usable host addresses does a /24 (255.255.255.0) subnet provide?
- A254 — the 256 addresses in the block minus the network and broadcast addresses
- B256 — every address in the block can be freely assigned to a host on the subnet
- C255 — every address in the block except the single reserved network address itself
- D253 — the block minus the network, the broadcast, and the reserved gateway address
Why this is the answer
A /24 holds 256 addresses; two are reserved (network and broadcast), leaving 254 usable. 256 counts the reserved pair, 255 forgets the broadcast address, and 253 wrongly reserves the gateway — the gateway simply uses one of the 254 usable addresses.
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