Wi-Fi & routers

Router isn't assigning IP addresses (DHCP not working)

When devices can't get any IP address at all from the router, it usually means DHCP is disabled, the address pool is full, or the router's DHCP service needs a restart, and devices will show a self-assigned address as a symptom.

Difficulty
Moderate
Time
15–30 minutes
DIY cost
$0
Pro cost
$0–$100

Symptoms

  • Multiple devices show an IP address starting with 169.254.x.x
  • No devices can get online despite the router appearing to work
  • Devices connect to Wi-Fi but sit at 'obtaining IP address' indefinitely
  • Problem appeared suddenly across many devices at once

Likely causes

  • CommonDHCP service disabled in the router's settingsThis service must be turned on for the router to automatically hand out IP addresses to connecting devices.
  • CommonDHCP address pool exhaustedIf the pool of available addresses is small and many devices are connected, new devices can't get an address until one frees up.
  • PossibleRouter's DHCP service crashed or needs a restartLike any router feature, DHCP can occasionally hang and need a reboot to recover.
  • PossibleA second router on the network also trying to run DHCPTwo DHCP servers on one network conflict and can prevent devices from getting a consistent address.

What to do

  1. Restart the router, which restarts its DHCP service along with everything else.
  2. Log into the router's admin page and confirm DHCP is enabled under LAN or network settings.
  3. Check the size of the DHCP address pool/range and increase it if it's set unusually small for your number of devices.
  4. Disconnect devices that don't need to be connected to free up addresses if the pool is full.
  5. If you have more than one router, ensure only one has DHCP enabled; disable it on any secondary router or switch it to access-point/bridge mode.
  6. On an affected device, try manually renewing its IP address (ipconfig /renew on Windows, or toggling Wi-Fi off and on) after confirming the router side is fixed.
  7. If DHCP still fails to assign addresses after these checks, a factory reset of the router will restore default DHCP settings, though it will erase other customizations too.

Tools and parts

  • Computer for checking network settings

When to call a pro

If DHCP issues persist after a factory reset, the router's networking hardware or firmware may be faulty and it's reasonable to replace it.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.