Unbound restarting on interface up/down, previous forum solutions not working

[HerkomerKlamm]

My Unbound is restarting frequently, even every 15 seconds under heavy load. This is being caused--I believe--by my WAN interface flapping. That is a separate issue I am trying furiously to resolve, but in the meantime I am trying to get Unbound not to restart with every WAN flap.

I have seen in previous forum posts that this can be caused by having DHCP registration enabled in Unbound. I do not have it enabled. I have also seen that it can be caused by having specific interfaces specified for Unbound to listen on. I did have this set, but on seeing the recommendation to use the recommended setting of 'all' (no specific interfaces set), I configured it that way. But the problem persists.

Any other ideas why Unbound is repeatedly restarting?

[lmoore]

More information please.

Probably best to resolve your flapping port before tackling other issues.

Have you rebooted OPNsense since resetting Unbound to listen on All interfaces?

What is your installed OPNsense version?

What NIC's do you have installed in your OPNsense firewall?

Describe the connection from OPNsense to your ISP.

Are there any clues in System -> Log Files -> General (in the drop-down list select Informational)?

[HerkomerKlamm]

I have done the workaround many have suggested to cure the flapping, by putting a switch between the modem & the OPNSense box. And I have another modem on the way to see if that really fixes it rather than works around it.

So right now I can't test this (because I can't afford to degrade the system for testing's sake).

For the record, I did not reboot OPNSense after changing Unbound to listen on All. I will definitely try that if this problem rears its head again.

Also for the record:

OPNsense 26.1.8_5-amd64

It's an AppNeta m70, & it has 2 Intel I211 1GbE ports with igb drivers, & 4 Intel X553 1GbE with ix drivers.

The original connection was Ethernet cable directly between modem & one of the X553 ports. Then tried putting the WAN port on other of the X553, then on each of the I211 ports. No luck there. Currently there is un unmanaged switch between the modem & the OPNSense, which has cured the flapping & also the Unbound restarts.

The only clues in the General log were the Ethernet reconnection up/down events (flapping) which corresponded with the Unbound restarts in the Unbound logs. When those went away, so did the Unbound restarts.

[dseven]

If you have any LAN interfaces that are tracking the WAN interface for IPv6 Identity Association, that would also trigger a restart of Unbound when the WAN interface bounces. You'd see something like this in the system log: "/usr/local/etc/rc.newwanipv6: plugins_configure newwanip (execute task : unbound_configure_do(,[wan,lan]))"