Use spare pi for redundancy help

[gonzo]

Hello,

I've got my Pi-Hole set up perfectly now and I'm really please with it. I'm having to use it as a DHCP server too as my ISP router doesn't let me do this.

The issue I have is if the Pi gets rebooted we can't use the internet for obvious reasons. Anyone I have a Pi Zero all setup with Pi Hole install, but I wanted to add it's IP address to the main Pi Holes DHCP scope for redundancy but it looks like I can't.

I was hoping to have their IPs as DNS1 and DNS2 in the DHCP scope.

Any other solution? I guess I could turn off DHCP and install a separate DHCP server on the 2 PCs.

Thanks

[jfb]

Secondary DNS Server for DHCP

I have it running in different environments (two of them at an enterprise level, one with more than 100 clients). They all run on Raspberry Pi hardware in various revisions. They never failed so far, so I wouldn't bother too much. A clever idea might be to set up two independent Pi-hole's and (two distinct devices in the same network) and set up those two IPs as "primary" and "secondary" servers. All devices should be able to resolve domains, even if one of them fails for some reason. The cost…

[gonzo]

Hi,

That's what I'm trying to do though.

I'm using the first Pi as a DHCP server, but I can't amend the DHCP settings for the DNS servers. I wanted to add the other PI (zero) as a secondary DNS server in the DHCP scope as the Backup.

The GUI doesn't seem to allow this.

[jfb]

You don't do this in the GUI - you do it in Linux with dnsmasq configuration files.

When you get this set up, then the DHCP Pi will give clients its own IP and the IP of the other Pi for DNS. That doesn't make it a secondary or backup server - the clients are free to use whichever PI they choose. If one goes down, they won't get a response from that one and will move to the other.

[gonzo]

Thanks, this sound right to me and what I need to achieve. So I have enable DHCP on Pi-Hole, where would I go to add/amend the DHCP scope via the commands line?

/etc/dhcp/dhclient.conf doesn't seem to be configured, but Pi-Hole is issued IPs to the network fine, I guess it is somewhere else?

Thanks

[jfb]

This is from the thread I referenced:

sudo nano /etc/dnsmasq.d/02-pihole-dhcp.conf

dhcp-option=6,Pi-holeIP,SecondaryDNSIP

sudo /etc/init.d/pihole-FTL restart

[gonzo]

Sorry I couldn't see your reference for some reason, however your commands have worked a treat.

Thanks you so much!