OpenWrt One: WAN link flapping

Installing and Using OpenWrt
1

On an irregular schedule, I am seeing the following on an OpenWrt One with 24.10.5

Mon Jan 26 01:19:52 2026 kern.info kernel: [143072.078182] mtk_soc_eth 15100000.ethernet eth0: Link is Down
Mon Jan 26 01:19:52 2026 daemon.notice netifd: Network device 'eth0' link is down
Mon Jan 26 01:19:52 2026 daemon.notice netifd: Interface 'wan' has link connectivity loss
Mon Jan 26 01:19:52 2026 daemon.notice netifd: Interface 'wan6' has link connectivity loss
Mon Jan 26 01:19:52 2026 daemon.notice netifd: wan (6316): udhcpc: received SIGTERM
Mon Jan 26 01:19:52 2026 daemon.notice netifd: wan (6316): udhcpc: entering released state
Mon Jan 26 01:19:52 2026 daemon.notice netifd: wan (6316): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "wan" } (Permission denied)
Mon Jan 26 01:19:52 2026 daemon.notice netifd: Interface 'wan' is now down
Mon Jan 26 01:19:53 2026 daemon.notice netifd: Interface 'wan6' is now down
Mon Jan 26 01:19:59 2026 daemon.notice netifd: Network device 'eth0' link is up
Mon Jan 26 01:19:59 2026 daemon.notice netifd: Interface 'wan' has link connectivity
Mon Jan 26 01:19:59 2026 daemon.notice netifd: Interface 'wan' is setting up now
Mon Jan 26 01:19:59 2026 daemon.notice netifd: Interface 'wan6' has link connectivity
Mon Jan 26 01:19:59 2026 daemon.notice netifd: Interface 'wan6' is setting up now

What can I do to debug this?

I am happy to re-flash the device or to do whatever debugging is needed. I just need it to be reliable, I can’t have it dropping out while working from home.

On the other end of eth0 is an Australian fibre NTD which supplies an Ethernet cable out and no diagnostics other than an LED

2

Did you start by checking the cable? That is a common cause of these types of issues - even when the cable might be high quality and/or new.

Replace the cable with a known good one and observe.

3

I will see if I can - part of this run is in the wall and I can’t pull it out at the moment.

4

Pulls through walls can in some cases accelerate issues insofar as kinks or other damage to the conductors (punctures, etc).

If you can’t replace the cable, try connecting a basic unmanaged switch between the two devices (only the two devices plugged in). If the flapping stops in the logs, it tells you the problem is either the cable or the ONT/NTD that is the problem. Sometimes you can also see the flapping on the upstream using the leds on the switch. You may still have intermittent outages because of the upstream issue, but the port flapping will stop since there will be a solid link between the switch and the OpenWrt One.

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5

This is a really good idea, thank you.

6

Solving this one as it was fixed after swapping the cable to the wall plate, luckily.

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7

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