Examkin

Question

Difficulty: Very hardWired and Wireless Network Issues

A systems technician is troubleshooting network access issues on a newly provisioned workstation connected to an enterprise wired network outlet. The workstation interface receives an IP address of 169.254.18.201169.254.18.201 with a subnet mask of 255.255.0.0255.255.0.0. The switch port link indicator shows a solid green status. When the technician configures a static IP address of 10.1.50.45/2410.1.50.45/24 with default gateway 10.1.50.110.1.50.1, ICMP pings to the default gateway succeed, but attempts to access external websites by domain name fail, and subsequent dynamic requests time out. Which of the following is the MOST likely cause of these symptoms?

  1. The DHCP server or relay agent is unreachable, and DNS server settings were omitted from the static IP configuration.Answer
  2. B
    The DNS server is attempting to lease dynamic IP addresses while the DHCP server is handling hostname resolution.
  3. C
    Adjacent 2.4 GHz wireless access points on channels 2 and 3 are causing co-channel interference on the Ethernet switch port.
  4. D
    The physical patch cable has experienced a total wire break, preventing link status detection and physical signaling.

Answer

The DHCP server or relay agent is unreachable, and DNS server settings were omitted from the static IP configuration.
The initial 169.254.x.x169.254.x.x address indicates APIPA, which occurs when a system cannot reach a DHCP server. Testing with a static IP address restores local IP communication to the default gateway, proving that physical layer cabling and switch port connectivity are fully functional. However, failure to resolve external domain names points directly to missing DNS server settings in the manual configuration profile.

Step-by-Step Solution

1
Analyze initial automatic IP assignment.
The assignment of 169.254.18.201169.254.18.201 with mask 255.255.0.0255.255.0.0 represents an Automatic Private IP Addressing (APIPA) self-assignment, confirming a failure to communicate with a DHCP server.
Clients assign APIPA addresses when DHCP discover/request packets fail to receive a DHCP offer/ack response.
2
Evaluate manual static IP testing results.
Configuring 10.1.50.45/2410.1.50.45/24 allows successful ICMP pings to default gateway 10.1.50.110.1.50.1, confirming Layer 1 physical link integrity and Layer 2 switch port VLAN mapping.
Successful local IP communication rules out cable cuts, bad NIC hardware, or dead switch ports.
3
Diagnose failure of external domain name resolution.
Inability to reach external destinations by domain name despite valid local routing indicates that DNS server addresses were not specified in the static network configuration.
Without configured DNS server IPs, domain names cannot be resolved to IP addresses required for internet routing.

Key Concept

APIPA Diagnosis and Network Service Role Identification
Rate this question

Topics

Wired and Wireless Network Issues

More questions from this topic