A desktop computer connected to an office Ethernet port is unable to communicate with exte… — CompTIA Network+

A desktop computer connected to an office Ethernet port is unable to communicate with external web servers or internal resources. A technician reviews the network interface status and observes an assigned IPv4 address of $169.254.108.99$ with a subnet mask of $255.255.0.0$ . Which of the following conditions is the most likely cause of this issue?

The client failed to contact a DHCP server and self-assigned an Automatic Private IP Addressing (APIPA) address.Answer
B
The host interface was manually assigned an invalid default gateway address.
C
The local switch disabled the Ethernet port due to an IP address conflict detection.
D
The subnet mask calculation omitted reserved network and broadcast addresses.

Answer

The client failed to contact a DHCP server and self-assigned an Automatic Private IP Addressing (APIPA) address.

When a network host configured for dynamic IP assignment sends DHCP discovery requests and does not receive a response from a DHCP server, the operating system assigns a link-local IPv4 address in the

169.254.0.0/16

range (APIPA). This indicates a failure in reaching or receiving a lease from the DHCP service.

Step-by-Step Solution

Analyze the IP address assigned to the host

The address

169.254.108.99

falls into the

169.254.0.0/16

IPv4 address block.

Addresses within

169.254.0.1

through

169.254.255.254

are designated specifically for APIPA link-local usage.

Identify the underlying trigger for APIPA generation

APIPA occurs automatically when a host configured for dynamic addressing cannot locate or obtain a lease from a DHCP server.

When DHCPDISCOVER packets receive no DHCPOFFER response within the timeout period, the OS assigns a link-local address to allow basic local segment connectivity.

Key Concept

APIPA Address Range and DHCP Failure Symptoms

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

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