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Explain CIDR in simple terms.
Explain CIDR in simple terms. CIDR writes an IP plus a prefix length, like 10.0.0.0/24, meaning the first 24 bits are the network part. A /24 holds about 254 usable hosts. A bigger prefix number means a smaller network. “I use CIDR to size subnets and to write tight security-group rules, so I don’t
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What this card says
Short answer
CIDR writes an IP plus a prefix length, like 10.0.0.0/24, meaning the first 24 bits are the network part.
Example
A /24 holds about 254 usable hosts. A bigger prefix number means a smaller network.
Say it in the interview
“I use CIDR to size subnets and to write tight security-group rules, so I don’t open 0.0.0.0/0 by habit.”
Why it matters
0.0.0.0/0 means “the whole internet”. Knowing CIDR stops you opening that by mistake.
Learn more in the lesson: 46.2 Networking Interview Questions