I have an asus router with a pi-hole on the network.
I was doing some work on my server and noticed that when pi-hole was down, I couldn’t access the internet. I was looking for some ideas online how to deal with this, but they said to have a second pihole on the network in case one is offline. Is that the only way to do it? Is there any way to have the network go back to normal if the pihole is offline?
No, that just creates time outs and delays when either of them is offline.
The proper way is to have a standby pihole that takes over the IP address of the main pihole when it goes down. It’s quite easy to achieve this with keepalived.