When Automatic Addressing Fails
Recognize APIPA addresses and common DHCP failures.
When DHCP Goes Quiet
Most of the time DHCP just works. But when no DHCP server answers, a device is left without proper settings. Recognizing the symptoms of a DHCP failure is a core troubleshooting skill. The clearest sign is a strange address starting with 169.254, called an APIPA address. This lesson explains APIPA and the common reasons automatic addressing breaks.
What APIPA Is
APIPA (Automatic Private IP Addressing) is a fallback built into Windows and other systems. If a device sends DHCP Discovers and gets no Offer, it gives itself an address from the range 169.254.0.1 to 169.254.255.254 with mask 255.255.0.0. APIPA lets devices on the same segment still talk to each other, but it provides no gateway and no DNS, so there is no internet access.
All lessons in this course
- What DHCP Hands Out
- The DORA Lease Process
- Scopes, Pools, and Reservations
- When Automatic Addressing Fails