Understanding the Root Cause
The Google WiFi system relies on the primary node (the one connected directly to your modem) to act as the central DHCP server. When this node restarts, it should theoretically reset its internal database of assigned IP addresses. However, bugs or race conditions in the firmware can cause the DHCP service to start before it has fully cleared previous lease entries. Consequently, when multiple devices attempt to reconnect simultaneously, they may receive duplicate assignments. This is particularly common in mesh setups where child nodes do not manage DHCP but rely entirely on the main unit for address distribution.
Additionally, static IP reservations configured on individual devices can exacerbate this issue if the DHCP server does not recognize them as reserved during the boot sequence. If a device holds an IP that the server thinks is free, a conflict arises. Understanding this dependency helps in diagnosing whether the issue is systemic (affecting many devices) or isolated (affecting specific hardware).
Related Resource
If you are managing complex network environments, understanding how DHCP interacts with other protocols is crucial. For more context on these underlying mechanisms, see Understanding the Dependency of DHCP on IP Protocol.
Step-by-Step Resolution Guide
Follow these steps to clear stale leases and re-establish proper IP assignment. This method targets the most common failure point: the cached lease table on the main node.
- Power Cycle the Main Node: Unplug the power adapter from the primary Google WiFi node (the one connected to the modem). Wait at least 60 seconds to ensure capacitors discharge and memory clears. Plug it back in and wait for the LED to turn solid white, indicating it is online.
- Restart Child Nodes: Once the main node is stable, unplug all secondary mesh nodes. Wait 30 seconds, then plug them back in one by one, allowing each to join the mesh before powering the next. This prevents simultaneous handshake requests that might trigger duplicate assignments.
- Renew DHCP on Client Devices: On the affected devices (computers, phones, smart TVs), disconnect from Wi-Fi and reconnect. For Windows PCs, open Command Prompt and run
ipconfig /releasefollowed byipconfig /renew. For macOS, go to System Preferences > Network, select Wi-Fi, click Advanced, and choose "Renew DHCP Lease."
If the problem persists, you may need to check for conflicting static configurations. Ensure no devices have manual IP settings that fall within the dynamic DHCP range. In some cases, rebooting the modem alongside the router helps synchronize the WAN connection state, which can indirectly affect DHCP stability.
Preventing Future Occurrences
To minimize the risk of duplicate IPs after future restarts, consider implementing DHCP reservations for critical devices. This assigns a fixed IP to specific MAC addresses, ensuring the server always recognizes them. While this requires initial setup, it reduces the load on the DHCP algorithm during high-traffic reconnection events.
Another effective strategy is to schedule regular maintenance windows. If you perform firmware updates or power outages, plan to reboot all nodes sequentially rather than simultaneously. This staggered approach allows the main node to stabilize its lease table before additional clients flood the network with requests.
Related Resource
For users dealing with similar reservation issues on different hardware, such as ASUS routers paired with Pi-hole, reviewing Issue Accessing Network IPs after DHCP Reservation on Pi Hole and Asus Routers may provide additional insights into reservation management.
Advanced Troubleshooting
If standard reboots do not resolve the issue, inspect the DHCP lease table via the Google WiFi app. Navigate to Settings > Network > Connected Devices to identify any duplicates. If two devices show the same IP, manually disconnect one and observe if the IP changes upon reconnection. If it remains static without being reserved, there may be a firmware bug requiring a factory reset of the main node.
Ensure your Google WiFi firmware is up to date. Older versions had known issues with lease expiration handling. Check for updates in the app under Settings > System > Software Update. Installing the latest patch often includes fixes for DHCP stability and mesh synchronization errors.
Frequently Asked Questions
Why do only some devices get duplicate IPs?
This usually happens because those specific devices were offline during the router's restart and are now competing for addresses that the server incorrectly marked as free. Devices that remained connected often retain their existing leases, avoiding the conflict entirely.
Can I fix this without restarting the router?
No, you cannot clear the server-side lease cache remotely without a reboot. However, you can force client devices to release their current IP and request a new one, which may resolve the immediate conflict if the server is still functional.
Does changing the DHCP range help?
Changing the DHCP range (e.g., from 100-250 to 50-200) does not fix duplicate IPs caused by stale leases. It only expands or shifts the pool of available addresses. You must still clear the existing conflicting entries to resolve the issue.
Is it safe to factory reset the Google WiFi node?
Yes, but it will erase all custom settings, including Wi-Fi names, passwords, and parental controls. You will need to set up the mesh system again from scratch using the Google WiFi app after the reset.
How long should I wait between unplugging and plugging back in?
Wait at least 60 seconds for the main node and 30 seconds for child nodes. This ensures that residual electrical charge dissipates and the internal memory is fully cleared, preventing rapid re-initialization errors.