Cisco Certified Support Technician (CCST) NetworkingNetworking FundamentalsEasy
A network technician is troubleshooting a client's workstation that is unable to access local network resources, but can ping its own loopback address. The technician observes that the workstation has an IP address of 169.254.100.50 and a subnet mask of 255.255.0.0. What is the most likely cause of this issue?
- AThe workstation is unable to obtain an IP address from a DHCP server.
- BThe workstation has a duplicate IP address on the network.
- CThe default gateway is incorrectly configured on the workstation.
- DThe network cable connected to the workstation is faulty.
Show answer & explanationAnswer & explanation
Correct answer: A. The workstation is unable to obtain an IP address from a DHCP server.
An IP address in the 169.254.0.0/16 range indicates an Automatic Private IP Addressing (APIPA) address. This typically occurs when a workstation is configured to obtain an IP address automatically but fails to communicate with a DHCP server.
Why the other options are wrong
- B. Duplicate IP addresses usually cause intermittent connectivity issues or conflicts, not a consistent APIPA address.
- C. An incorrect default gateway would prevent access to external networks, but local network resources should still be accessible if an IP address was properly obtained.
- D. A faulty network cable would generally result in no network connectivity at all, not an APIPA address.
APIPA (Automatic Private IP Addressing)
APIPA is a feature in Windows operating systems that automatically assigns an IP address to a client when no DHCP server is available. The assigned IP address is in the 169.254.0.0/16 range.
- Automatically assigns IP addresses when DHCP fails.
- IP addresses are in the 169.254.x.x range.
- Allows communication only within the local subnet.
Memory trick: DHCP Dreams, APIPA Reality for network setup.