WAN goes down and doesn't come back up

My wan and wan6 interfaces recently stopped, maybe the ISP was changing something on their side, I’m not sure.

The router was otherwise working fine, interacting with local LAN devices.

However, it did not try to bring up the wan and wan6 interfaces again, they stayed down for hours

When I came home and found it in this state, I went to the web interface (LUCI) and clicked the ‘Connect’ button next to the WAN interface and it came up immediately. I didn’t need to reboot or anything.

Why didn’t it come back up by itself?

How can I configure it to try and bring the interface back up automatically after an ISP issue?

Also, if there isn’t currently a configuration option to make it keep the interface up, is it possible to write a small cron job that will bring up the wan after a failure?

For example, the cron job could take the ip route output and if there is no default entry it would know the interface is down and try to bring it up.

Hello, in my case, Watchdog tests every 15min the line to an external address. If this is not possible, an automatic reboot is performed after one hour. There, different states can be set as to how to proceed. After a reboot, it should theoretically work again.