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LFCS · Question #446

Which of the following Class B IPv4 networks are reserved by IANA for private address assignment and private routing? (Select TWO).

The correct answer is D. 172.16.0.0 E. 172.20.0.0. IANA reserves the IPv4 Class B range 172.16.0.0 through 172.31.255.255 (a /12 network) for private address assignment and routing within private networks.

Submitted by devops_kid· Apr 18, 2026Networking

Question

Which of the following Class B IPv4 networks are reserved by IANA for private address assignment and private routing? (Select TWO).

Options

  • A128.0.0.0
  • B169.16.0.0
  • C169.254.0.0
  • D172.16.0.0
  • E172.20.0.0

How the community answered

(38 responses)
  • A
    3% (1)
  • B
    5% (2)
  • D
    92% (35)

Why each option

IANA reserves the IPv4 Class B range 172.16.0.0 through 172.31.255.255 (a /12 network) for private address assignment and routing within private networks.

A128.0.0.0

`128.0.0.0` is a public IP address range and is not reserved for private use.

B169.16.0.0

`169.16.0.0` is a public IP address range and is not reserved for private use.

C169.254.0.0

`169.254.0.0` is the Automatic Private IP Addressing (APIPA) range, used for link-local addresses, but it is not one of the RFC 1918 private address ranges for general network routing.

D172.16.0.0Correct

The `172.16.0.0` network is part of the RFC 1918 private IPv4 address range `172.16.0.0` - `172.31.255.255` (a /12 prefix), which is reserved for private use and not routable on the public internet.

E172.20.0.0Correct

The `172.20.0.0` network also falls within the RFC 1918 private IPv4 address range `172.16.0.0` - `172.31.255.255` (a /12 prefix), designated for private networks.

Concept tested: RFC 1918 Private IP Address Ranges (Class B)

Source: https://datatracker.ietf.org/doc/html/rfc1918

Topics

#IPv4#Private IP addresses#RFC 1918#Networking fundamentals

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