Question

Difficulty: MediumWired and Wireless Network Issues

Match each network symptom or issue on the left with its most likely underlying cause on the right.

  • A workstation auto-assigns an IP address of 169.254.42.88 after connecting to an Ethernet port.DHCP server scope exhaustion or unreachability.
  • Users experience frequent drops and poor throughput on a 2.4 GHz wireless network in an office with four nearby access points set to Channel 6.Co-channel interference and frequency overlap.
  • A desktop experiences intermittent network access alongside operating system pop-up notifications warning of duplicate network addresses.IP address conflict from duplicate static assignment.
  • A new Cat6 copper cable connection spanning 120 meters drops down to 100 Mbps instead of establishing a 1 Gbps link.Signal attenuation and distance limitation breach.

Answer

The client auto-assigning 169.254.x.x matches DHCP server scope exhaustion or unreachability; multiple access points operating on Channel 6 match co-channel interference; system notifications warning of duplicate addresses match IP address conflict from duplicate static assignment; and a Cat6 run over 120 meters dropping link speed matches signal attenuation and distance limitation breach.
Each item accurately pairs the observed networking symptom with its underlying root cause: APIPA (169.254.x.x) signals DHCP unreachability; multiple APs on channel 6 create 2.4 GHz co-channel interference; duplicate address pop-ups signify identical IP address assignment; and exceeding the 100m Ethernet specification leads to attenuation and degraded link speeds.

Step-by-Step Solution

1
Analyze APIPA behavior
An IP starting with 169.254.x.x is an Automatic Private IP Address (APIPA) generated when a DHCP server cannot be reached or has no available scope.
Identify the cause for fallback self-assigned addressing.
2
Evaluate wireless channel configuration
Multiple adjacent access points using Channel 6 lead to heavy co-channel interference on the 2.4 GHz band.
Determine the impact of non-distributed channel planning.
3
Identify IP collision symptoms
Duplicate address warnings and dropouts indicate two endpoints sharing an identical IPv4 address.
Recognize signs of duplicate static assignment conflicts.
4
Check physical layer distance constraints
Category 6 Ethernet cabling has a maximum certified distance limit of 100 meters (328 feet) for gigabit speeds; 120 meters exceeds this spec causing attenuation and auto-negotiation fallbacks.
Apply twisted-pair distance limitations.

Key Concept

Wired and Wireless Network Troubleshooting
Rate this question