Linksys Velop / Rasp Pi / Pi-hole DNS issue

[S6PNJ]

I'm having a few issues recently with my Rasp Pi Zero 2 W Pi-hole as it keeps randomly crashing and won't allow me to go to the Pi-hole dashboard or login via VNC - that's the issue that then leads me onto the real question. My Linksys Velop mesh system is configured to use the Pi-hole as the DNS. I only have one DNS configured, all other DNS 'fields' are configured to 0.0.0.0

So why, when my Pi-hole crashes (and I see adverts etc, can't browse to the Pi-hole dashboard) am I still able to get to the internet and browse pages I've never looked at before? I've done an 'ipconfig /all' on my laptop and it gives my DNS as 192.168.0.1, ie the IP of my Default Gateway and DHCP server of the Velop mesh node (the node that connects to my FTTP). DNS is still configured as 192.168.0.14 (my Pi-hole address).

Is the Velop Mesh somehow 'finding' a default DNS to allow it to still function? Or why, if my Pi-hole is no longer working, do I get a DNS from somewhere else?

[ARHarh]

I can't help with how your DNS is working. But I can offer advice that is is probably the SD card in your pi that is failing. Take a backup of pihole (if you can) and install to a new card and restore the backup.

[jimmyjimjim]

I'm curious to see if the pi-hole has completely crashed. If you unplug it, can you still reach sites? I'm wondering if it's possible that just some services have stalled, eg VNC and the management interface.

As above though, SD card.

I'm running pi-hole as a container in my NAS. No SD card to corrupt.

[WrekinCrew]

RPi SD cards last longer if you disable Pi-hole logging.

[Chimune]

On the laptop use "nslookup" to get ip of a public domain name and see whats answering