CCNA Plan

CCNA practice question: Network Fundamentals

Network FundamentalsDifficulty 2/5

What is the network address for host 172.16.45.200 with a /20 mask?

  1. A172.16.32.0
  2. B172.16.40.0
  3. C172.16.48.0
  4. D172.16.45.0
Show answer and rationale

Correct: A. A /20 mask is 255.255.240.0, so the interesting octet is the third with block size 256 − 240 = 16. Multiples of 16 up to 45 are 0, 16, 32, 48; 45 falls in the 32 block, so the network is 172.16.32.0 and the broadcast is 172.16.47.255.

  • D — That would require a /24 or longer mask.
  • B — 40 is not a multiple of the block size 16.
  • C — 48 is the start of the next block; 45 is below it.

Concept being tested

Network components, topologies, cabling and interface issues, TCP vs UDP, IPv4 addressing and subnetting, IPv6 addressing and types, wireless principles, virtualization, switching concepts. — 20% of the exam. Study guide for Network Fundamentals.

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Primary references

  1. CCNA Exam v1.1 (200-301) Exam Topics — Cisco Systems · primary · retrieved 2026-09-21, verified 2026-09-21
  2. RFC 4632 — Classless Inter-domain Routing (CIDR) — IETF · government · retrieved 2026-09-21, verified 2026-09-21
Draft — pending editorial reviewHow we verify facts