Glossary · Networking

APIPA (Automatic Private IP Addressing)

APIPA is the fallback in which a device without a DHCP answer assigns itself an address in 169.254.0.0/16 for local-only communication.

Updated October 6, 2026

APIPA (Automatic Private IP Addressing) is a feature, notably in Windows, that assigns an interface an address from 169.254.0.0/16 when it is set to obtain an address automatically but receives no reply from a DHCP server. The general standard behind it is IPv4 link-local addressing.

Why it matters

Seeing an address starting 169.254 is a quick diagnostic sign: the device is connected to the network but did not get a proper lease. It can talk to other devices that are also on the same segment and also self-assigned, but it has no default gateway and so cannot reach the internet. The device picks an address at random, checks for conflicts with ARP, and keeps retrying DHCP in the background.

Example

C:\> ipconfig
   IPv4 Address. . . . : 169.254.37.201
   Subnet Mask . . . . : 255.255.0.0
   Default Gateway . . : (blank)

Possible causes are a stopped DHCP server, an exhausted address pool, a bad cable or Wi-Fi association, or a switch port or VLAN that blocks DHCP.

Common misconceptions

  • A 169.254 address is not a sign that the internet is down; it points at the local DHCP step.
  • APIPA is not the same as a private RFC 1918 address.
  • Setting a static address manually avoids this fallback.

Get notified when this term updates

Plus occasional practical tips on uptime and monitoring, nothing else. Unsubscribe anytime.

Keep reading

Glossary · Networking802.1X (Port-Based Network Access Control)802.1X is an IEEE standard that blocks a network port until the connecting device authenticates, commonly with a RADIUS server.Glossary · NetworkingAccess Point (Wireless AP)A wireless access point is a device that connects Wi-Fi clients to a wired network, acting as the bridge between radio and Ethernet.Glossary · NetworkingAnycast RoutingAnycast announces the same IP address from many locations, so network routing sends each user to a nearby site and absorbs traffic floods.

This page is general information written by our editorial team and updated when documentation changes. Servers and providers differ, so test changes safely first. See our editorial policy and disclaimer.