I have a typical 3 VLANs 10, 30, 40 setup. they are isolated with the exception that VLAN10 should be able to access the other 2 interfaces. These VLANS are setup as bridges with no DHCP servers and each has an untagged port assigned to it. Attached to each VLAN port is a DDWRT router that runs a DHCP server with wan disabled.
I have a DNS server attached to the VLAN10 router 192.168.10.230. Is it possible to have all of these interfaces , 10, 20, and 30 use this DNS server? This dns server is a pihole.
the ddwrt 192.168.(10, 30, 40).2 routers are forwarding their DNS requests to their gateway 192.168.(10,30,40).1 on the openwrt. I have tried to have the openwrt router use the DNS server to no avail. I this is possible I will share my configs. Otherwise, please suggest a change in topology. Thanks in advance
I will try to rephrase my question(s).
Where do I set the DNS server for all the interfaces.
Is there a common place?
Does it matter if these interfaces are not DHCP servers?
If the DNS is on one of these interfaces, does that cause catch 22?
I have unsuccessfully tried few options in the GUI. I want to intercept all DNS queries and route them to my local pihole.
You can technically set the DNS with DHCP-Options for each Interface, if that is what you mean.
Go to LuCi > Network > Interfaces > Edit > DHCP Server > Advanced Settings > DHCP-Options
And add 6,192.168.10.230 if that is your DNS server.
Be careful that your DNS itself has setup upstream DNS server IPs directly, otherwise you'll going to end up with a loop.
Here is an example of how the GUI looks like for the DHCP-Options field:
Regarding intercepting and catching all DNS queries, that seems more likely to be done with firewall settings. Perhaps someone else can explain that part better, since I don't personally use it.
Installing the DNS over HTTPS app has an automatic setting to catch all DNS queries, but not sure that applies for your use case.
Thanks for the reply,
My interfaces are not DHCP servers. Therefore I do not have the option of setting the DHCP options.