Hello everyone,

first time ever posting on lemmy, feels good 😉

I have a question regarding DHCP in my local network.

My current setup is as follows:

  • DHCP provided by router (Fritz!Box 7490)
  • DNS provided by pi-hole hosted on a raspberry pi
  • DHCP pushes the IP of the raspberry via DHCP to all clients

My problem is: When the raspberry pi (running pi hole) is down for any reason, none of my devices has internet access anymore. This is due to the fact that the Fritz!Box router (aka DHCP server) has no option to push a secondary DNS as a fallback to its clients.

One option would be to buy another router which has the option to push a secondary DNS, which I would prefer to avoid, since otherwise I am happy with the Fritz!Box.

So I am looking for alternative configurations with my existing hardware. I could for example use pi holes DHCP. Or I could use the DHCP server package of a synology NAS which is also part of my local network. Or is there another option, maybe using some DHCP service on the raspberry pi or in a docker container or something like that? Does anyone have experience with one of these setups and can tell me if it is possible to provide the clients with two (prioritized) DNS options? What would you recommend? Thanks!

  • @[email protected]English
    2•1 year ago

    When the raspberry pi (running pi hole) is down for any reason

    You can have 2 DNS servers provided over DHCP assignment, if this is really an issue for you (ideally it shouldnt) you should be running 2x PiHoles for failover protection, that way you can take 1 offline and all devices will auto swap to the second one for DNS.

    This will also horizontally scale your DNS querying, as devices will just 50/50 flip flop between the two while both are online and it will sort of auto-load balance.

    Largely speaking thats your best bet though, just 2x PiHoles for failover protection.

    For DHCP just use one of the pi-holes DHCP, or your routers, or whatever, they all largely perform the same but I personally find the pi-hole’s DHCP settings to be easiest to work with (you can even super fast modify them by SSHing in and using nano/vim to text edit the config file, so instead of using a UI you can just copy-paste all the entries in quickly)

    If you need to take the DHCP pi-hole offline, you can just flip DHCP on for the second one, however as long as new devices arent connecting you don’t actually need the DHCP server online once everyone has an IP assigned until their registration time is up (24 hours by default) so as long as you get the pi-hole back online quickly, you’re network typically wont even have a problem.