Adblock package on OpenVPN client - how do I test

I have other issues open on this forum but this thread will address a new unique issue and does not deal with the other projects I am working on and have posted about here. Ok, now the details ...

How do I test to see if adblock is working on my "dedicated to VPN client" OpenWRT(2) router? It doesn't seem to make a difference that I can see when installed on this dedicated OpenVPN client on router OpenWRT(2). I have established the OpenWRT(2) as a secondary router with its own unique SSD where anyone in my family who attaches is connected to the VPN.. This secondary OpenWRT(2) router has its WAN port plugged in the LAN of my main or primary OpenWRT(1) router which serves as a simple access point for my OpenWRT(3) router which is configured as a wifi client that receives signals from the master telco fiber optic router via a parabolic antenna that is pointed to the telco router in the distance.

So how do I test adblock and if it's not working, is there something special required to add it to a router set up as a VPN client? Note that the VPN client is configured where DHCP presents the two unique DNS servers of the VPN provider which in my very limited knowledge of the process means that the DNS requests may be direct routed from the workstations. I set the network up this way originally, with the workstation clients communicating directly with the VPN DNS because all other configurations I seemed to come up with showed DNS leaks and I was flagged as being in my true location, shown via DNS leak tests.

Pick one or two blocked domains (e.g. from /tmp/dnsmasq.d/adb_list.overall) and test them on your clients (e.g. nslookup or dig A +short; be aware that DNS based blocking can never catch all ads.

Thanks, does the DNS of the OpenWRT router need to be defined as the client DNS server for adblock to work or will Adblock intercept the data if the clients DHCP points to non-OpenWRT controlled DNS servers found on the VPN provider?

By default, no - but this can be enabled in its configuration options.

I don't have any files listed under that directory so I assume something is not configured right.

I was able to remove the pointer to the VPN DNS servers from the DHCP configuration file, add a pointer to those same servers in the WAN interface and point to this VPN Client server in the DHCP config. I then say that the leak was back but I deleted the WAN6 interface and the leak went away again (WAN6 must override ipv4 DNS servers), so now it seems like it should be routing the DNS traffic through this secondary router VPN client, but I don't see that test file you told me to look for.

Nevermind, I found it, it was located at /tmp/adb_list.overall. I tried a blocked domain and it seems to be working now.