Hi,
I'm trying to figure out how to set up a service like pi-hole and one of the prerequisits seems to be to have admin access to the router to make the correct DNS entries.
Unfortunately, the router provided by my ISP doesn't grant me access to these settings - is there a way around that, and what would it involve? I do have a hybdrid router (DSL + LTE connection), that's (according to my ISP) the reason DNS settings are locked.
Definitely this. If you're absolutely sure you can't change config on the router, then you just treat it like a modem. Let it serve up one, single DHCP lease to your own router and run your network off of that.
If OP's router is so basic that they can't change DNS server addresses, there are chances they can't disable the builtin dhcp server either. 2 DHCP servers on the same network will not end well.
I think the only way is to manually set DNS servers on each client.
If you read the link, you will understand that you can decide for every network interface a personnalize DNS.
Not simply a DNS to the whole network, or by machine.
Also, 99.99% sure that any modem router box combo can disable the DHCP and act as a bridge.
Note: the question I wrote was a guenuine one, and not sarcasm.