Wi-Fi & routers

IP address conflict or DHCP error on the network

An IP conflict happens when two devices try to use the same address on your network, usually from a static IP set manually or a router glitch, and is fixed by restarting devices or letting the router reassign addresses automatically.

Difficulty
Moderate
Time
10–20 minutes
DIY cost
$0
Pro cost
$0–$100

Symptoms

  • Device shows a message like 'IP address conflict' or 'duplicate IP address'
  • A device suddenly loses network access others still have
  • Network becomes unstable when a specific device is turned on
  • Windows shows a yellow warning triangle on the network icon

Likely causes

  • CommonA device set to a static IP that another device is also usingManually assigning the same address to two devices, or one overlapping the router's automatic range, causes conflicts.
  • CommonRouter's DHCP lease table got confused after a restartRouters hand out temporary IP addresses, and a device reconnecting quickly can sometimes grab a stale one.
  • PossibleTwo routers or a router plus modem-router combo both handing out addressesRunning two DHCP servers on the same network causes overlapping assignments.
  • PossibleDevice reconnecting to network after being away for a long timeA returning device may try to reuse its last known IP, which was reassigned to something else.

What to do

  1. Restart the device showing the conflict; this usually releases and renews its IP address automatically.
  2. If that doesn't work, restart the router to reset the DHCP address table for the whole network.
  3. On Windows, open Command Prompt and run 'ipconfig /release' then 'ipconfig /renew' to force a new address.
  4. On Mac, go to Network settings, click the connected network, then Advanced, TCP/IP, and click 'Renew DHCP Lease'.
  5. Check whether any device on the network has a manually assigned (static) IP address, and make sure it falls outside the router's automatic DHCP range, found in the router's LAN settings.
  6. If you have two routers on the network, make sure only one has DHCP enabled; put the second in bridge or access-point mode.
  7. If conflicts keep recurring, increase the router's DHCP address pool size in its settings if it's set unusually small.

Tools and parts

  • Computer for command line commands

When to call a pro

If conflicts happen constantly across many devices, a home networking technician can review your router configuration, especially in homes with multiple routers or smart-home hubs.

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.