I’m using a RUX11 in an installation. It has been up for a couple of years, but the router was replaced in August 2025. The configuration was restored from a backup so the setup is pretty much as it’s always been.
At some point between August 2025 and March 2026 the DHCP server stopped working. No wired or wireless clients get addresses; neither the ones reserved by MAC address or new clients with no reservation.
I have tried turning on the “force” setting for the DHCP server to no avail. I have also tried disconnecting all clients, rebooting, etc. There are no rogue DHCP servers. Clients just get self-allocated 169.254 addreses.
It seems utterly absurd that this would work and then stop working. Has anyone seen this behaviour before? What’s going on?
The configuration is very simple, most settings as default, the only thing worth noting is that there are two LAN IP ranges; 10.23.3.0/24 and 192.168.1.0/24. It’s only the first one of those that’s supposed to have DHCP. They are both br-lan, this is just to acommodate some clients whose IP configuration we couldn’t change. (obscure control stuff)
Thank you for reaching out. To help us investigate the DHCP issue further, could you please clarify the following points:
Was the configuration restored from an older device or backup? If so, was it created on the same firmware version as the current device?
What firmware version is currently running on the router?
Have there been any recent changes to the network topology, such as new switches or devices that could act as a rogue DHCP server?
If possible, could you test DHCP on just a single LAN subnet by temporarily disabling the second one and let us know whether clients receive IP addresses?
Your answers will help us pinpoint the cause more effectively. I look forward to your reply.
The configuration was restored from a backup as the previous RUTX11 was stolen. I don’t remember what firmware it was running when the backup was made, but I would assume it was an older version.
The current version is RUTX_R_00.07.12.3
There are no topology changes.
I tried disabling the second LAN and noticed no difference.
For testing purposes, could you try upgrading the device to the latest stable firmware version with the Keep settings option disabled , and then check whether the DHCP server starts issuing leases correctly? Performing the upgrade without preserving the existing configuration helps ensure that no legacy or backup-related settings interfere with the system.
After the upgrade, the device will return to its default configuration, so you may need to reconfigure the necessary settings for testing. This step will help determine whether the issue is related to the current firmware version or an existing configuration backup.