It seems I still having some issues with stubby on firmware 3.208.
So Im running this firmware quite a while on the flint, and I also made some changes myself and did some testing.
Now I do use wireguard with the mullvad config, along with nextdns and I have checked the override dns aswell, and im not using adguard or vpn policies.
Ipv6 is disabled, I noticed in /etc/stubby/stubby.yml a ipv6 dns entry, I commented out this line.
I also disabled rebind protection both on the side of nextdns as on the router.
I also made sure to use unique metrics for each interface (I readed somewhere on the openwrt forums that it is important, it did however fixed my vlan dropping issue)
So I decided to download a big game on steam and having my tv on aswell, the tv is connected on a vlan on its own port but the streaming tv box is on a switch which comes straight from the modem (so an concurent connection).
My result was kinda interesting, I noticed jittering and due the jittering stubby became unresponsive in a way that it couldn’t connect to the internet, once when I restarted the service with
/etc/init.d/stubby restart my dns was back working and also the strange jittering disappeared.
So I went further looking through the forums and I saw somewhere a post to higher the maximum packets for contrack because somebody had issues with torrents, so I set this to 65536 and the jitter is gone when I download.
However now I notice stubby goes down faster often what I notice is the following behaviour:
When it goes down I restart the service, after approx 15 minutes it happens again, but after this it can work like a half day again.
Someone has a idea what it could be?
Btw I noticed on the openwrt branch that there is a newer version of stubby perhaps it can be ported?