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Zorluk: Çok zorNetwork Host Services and Server Roles

Following a scheduled power maintenance window at a branch office, multiple workstation users report that they cannot access internal file shares or connect to the internet. A technician runs `ipconfig /all` on an affected client machine and observes an IP address of 169.254.108.45169.254.108.45, a subnet mask of 255.255.0.0255.255.0.0, and a blank Default Gateway entry. Upon inspecting the main local host server, the technician observes that a newly installed centralized logging service failed to launch because UDP port 67 was already bound by another process that crashed during reboot. Which of the following best explains the root cause of the network connectivity failure on the workstations?

  1. The DHCP server service on the local host server failed to start, preventing client workstations from obtaining valid IP configuration leases and causing them to auto-assign APIPA addresses.Cevap
  2. B
    The DNS server service failed to lease dynamic IP addresses and default gateway assignments to the local workstations.
  3. C
    The web server role was configured to listen on UDP port 67 instead of TCP port 443, preventing secure communication with local hosts.
  4. D
    The workstation adapter experienced a static IP collision and defaulted to a public, globally routable APIPA address.

Cevap

The DHCP server service on the local host server failed to start, preventing client workstations from obtaining valid IP configuration leases and causing them to auto-assign APIPA addresses.
The correct answer identifies that the failure of the DHCP server role (which operates on UDP port 67) prevents client workstations from receiving dynamic IP address leases, default gateways, and DNS settings. When clients fail to communicate with a DHCP server, modern operating systems automatically assign a link-local APIPA address (169.254.x.x169.254.x.x), allowing local subnet communication if configured properly, but preventing off-subnet network and internet routing.

Adım Adım Çözüm

1
Analyze client IP configuration symptoms from output.
Workstations received an IP address in the 169.254.0.0/16 range with no default gateway.
Addresses starting with 169.254.x.x are APIPA (Automatic Private IP Addressing) addresses assigned automatically by the host OS when DHCP server discovery fails.
2
Correlate server-side service states with port 67 binding conflict.
UDP port 67 is the standard port for DHCP server listening requests.
A socket conflict or crash related to UDP port 67 prevents the DHCP host server role from listening to incoming DHCPDISCOVER broadcasts.
3
Determine the impact on local host services.
Without a functional DHCP server service, clients cannot lease valid IP parameters, leading to local-link-only fallback (APIPA) and no gateway routing.
This directly explains both the network isolation and the specific APIPA configuration observed across branch workstations.

Anahtar Kavram

DHCP Server Role and APIPA Fallback Behavior
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