Question

Difficulty: EasyTroubleshooting IP Addressing and DHCP Services

A user connects a laptop to a wired network jack in a remote conference room but cannot access any internal or external network resources. A technician executes `ipconfig /all` on the workstation and receives the following output:

IPv4 Address. . . . . . . . . . . : 169.254.22.81
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . :

Which of the following is the most likely cause of this issue?

  1. The client failed to reach a DHCP server and generated an Automatic Private IP Addressing (APIPA) address.Answer
  2. B
    The default gateway address was statically misconfigured on a different subnet than the host workstation.
  3. C
    The host workstation is missing a valid host (A) record entry on the primary internal DNS server.
  4. D
    A duplex mismatch between the host network interface card and the switch port is corrupting all frame headers.

Answer

The client failed to reach a DHCP server and generated an Automatic Private IP Addressing (APIPA) address.
An IPv4 address beginning with 169.254 (specifically within 169.254.0.1 to 169.254.255.254) indicates that the host operating system self-assigned an Automatic Private IP Addressing (APIPA) address. This occurs automatically when a client configured for DHCP fails to receive a DHCPOFFER message from a DHCP server.

Step-by-Step Solution

1
Examine the IP address snippet obtained from ipconfig.
The IPv4 address is 169.254.22.81 with subnet mask 255.255.0.0.
Addresses within the 169.254.0.1 – 169.254.255.254 range are reserved for APIPA (link-local) addressing.
2
Determine why APIPA was assigned.
The client attempted to obtain an IP via DHCP, but no DHCP server responded to the DHCPDISCOVER broadcast.
Operating systems automatically assign an APIPA address when dynamic configuration fails so local link communication remains possible.

Key Concept

APIPA (Automatic Private IP Addressing) Diagnosis
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