A network technician is troubleshooting a newly connected desktop computer in an office environment that cannot access internal file shares or external websites. The workstation's network interface card displays an active green link light with occasional activity flickers. Running the command `ipconfig /all` on the machine displays an IPv4 address of 169.254.112.45 and a subnet mask of 255.255.0.0. Which TWO of the following are the most likely causes of this network connectivity issue?
- The local DHCP server is offline or experiencing scope exhaustion.Cevap
- BThe network interface card has suffered a complete physical transceiver failure.
- A network security policy or VLAN misconfiguration is blocking DHCP traffic on UDP ports 67 and 68.Cevap
- DThe primary DNS server is down, preventing IP address leases from being assigned.
Cevap
The client machine has assigned itself an Automatic Private IP Addressing (APIPA) IPv4 address (169.254.112.45), indicating that physical Layer 1 connectivity is functional (supported by the active link lights), but Layer 3 DHCP configuration has failed. The most likely causes are an unresponsive DHCP server (or exhausted IP pool) and a network device or VLAN setting filtering DHCP traffic on UDP ports 67 and 68.
An IP address within the 169.254.x.x block signifies APIPA auto-configuration due to DHCP negotiation failure. Since physical link lights verify active Layer 1 connectivity, the issue lies at Layer 3/4 network host services: either the DHCP server itself is unresponsive/exhausted, or intermediary network infrastructure is dropping DHCP traffic on UDP ports 67 and 68.
Adım Adım Çözüm
Anahtar Kavram
APIPA Interpretation and DHCP Troubleshooting