CCNA Plan

Network Fundamentals: practice questions

5 original questions · 0 editor-approved · every choice explained.

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Blueprint-mapped questions with full rationales for every choice.

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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.
Network FundamentalsDifficulty 3/5

How many usable host addresses are in a /31 subnet on a point-to-point link, and why?

  1. A0, because network and broadcast consume both addresses
  2. B2, because RFC 3021 allows both addresses to be assigned on point-to-point links
  3. C1, because one address is reserved for the broadcast
  4. D4, because /31 has four addresses
Show answer and rationale

Correct: B. A /31 has two addresses. RFC 3021 permits using both on point-to-point links, since no broadcast address is needed there. Cisco IOS supports this with the ip address ... 255.255.255.254 form.

  • A — The classic 2^n − 2 rule does not apply to /31 per RFC 3021.
  • C — No broadcast address is reserved on a /31 point-to-point link.
  • D — 2^(32−31) = 2 addresses, not 4.
Network FundamentalsDifficulty 2/5

Which address is in a private range defined by RFC 1918?

  1. A172.33.10.1
  2. B192.169.5.5
  3. C10.255.254.1
  4. D169.254.10.10
Show answer and rationale

Correct: C. RFC 1918 reserves 10.0.0.0/8, 172.16.0.0/12 (172.16–172.31) and 192.168.0.0/16. 10.255.254.1 is inside 10.0.0.0/8.

  • A — 172.33 is outside 172.16.0.0–172.31.255.255.
  • B — 192.169.0.0 is outside 192.168.0.0/16.
  • D — 169.254.0.0/16 is link-local (APIPA), not RFC 1918.
Network FundamentalsDifficulty 2/5

A network engineer captures traffic and sees a three-way handshake before data transfer. Which transport protocol and characteristic does this indicate?

  1. AICMP; error reporting
  2. BUDP; flow control
  3. CUDP; connectionless delivery
  4. DTCP; connection-oriented, reliable delivery
Show answer and rationale

Correct: D. The SYN, SYN-ACK, ACK handshake establishes a TCP connection. TCP provides reliability, ordering and flow control; UDP has no handshake.

  • C — UDP does not perform a handshake.
  • A — ICMP is a network-layer control protocol, not transport.
  • B — UDP has no flow control.
Network FundamentalsDifficulty 3/5

Which IPv6 address type is automatically configured on every IPv6-enabled interface and is required for neighbor discovery?

  1. ALink-local fe80::/10
  2. BMulticast ff02::1
  3. CGlobal unicast 2001::/16
  4. DUnique local fc00::/7
Show answer and rationale

Correct: A. Every IPv6 interface derives a link-local address in fe80::/10 (typically via EUI-64 or a random ID). Neighbor Discovery and routing protocol hellos use link-local addresses; they are never routed off the link.

  • C — Global addresses are optional and assigned by SLAAC/DHCPv6/manual config.
  • D — Unique local addresses are optional private addresses.
  • B — ff02::1 is the all-nodes multicast group, not an interface address.

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
  3. RFC 3021 — Using 31-Bit Prefixes on IPv4 Point-to-Point Links — IETF · government · retrieved 2026-09-21, verified 2026-09-21
  4. RFC 1918 — Address Allocation for Private Internets — IETF · government · retrieved 2026-09-21, verified 2026-09-21