Interview Questions/Phone Screen/What does /24 mean in CIDR?
BeginnerPhone
1 min

What does /24 mean in CIDR?

NetworkingIPv4Subnetting
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Interview Question

In CIDR notation, what does a /24 signify and roughly how many usable IPv4 addresses are in such a subnet?

Key Points to Cover
  • /24 means 255.255.255.0 (24-bit network mask)
  • 256 total addresses; ~254 usable (excluding network and broadcast)
  • 8 bits remaining for host addresses (2^8 = 256)
Evaluation Rubric
States /24 equals 255.255.255.040% weight
Mentions ≈254 usable addresses40% weight
Explains the bit calculation20% weight
Hints
  • 💡Think: 32 total bits; 24 for the network portion.
Potential Follow-up Questions
  • What about /16 or /8?
  • How would you subnet a /24 into smaller networks?
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