Running Pi-hole Version v3.2.1 Web Interface Version v3.2.1 FTL Version vDev ((no, v2.13 ) and, as far as I can tell, it's working fine. Statistics show ad-domains being blocked. When I test on Android phone, I do get ads when on 3G/4G (as expected), but none when on wifi (again, as expected).
However, when I add a domain to the blacklist through Pi-hole's web interface, I'm still able to access that site. It doen't matter if I add it "exact" or "wildcard". Same result. This gives me the idea in my configuration there's still another way to find a domain and load its web page, even though I blacklisted the domain in Pi-hole.
That's not the point. I was just using 3G/4G to illustrate Pi-hole is working. What I don't understand is that when I blacklist a domain, I'm still able to access it. Perhaps it's stored in cache memory somewhere.
That's my assumption as well. Can you try to access the blocked page on a device you have not used so far to test this? Alternative is to block something you have not visited before and then try visiting this site to exclude that it can be a cache issue.
If it still doesn't work, please share the most recent lines of /var/log/pihole.log on your Pi-hole after trying to visit the blacklisted domain. If it is not there, your device might be using another DNS server and bypass the Pi-hole.
Using Firefox 58 (Quantum) browser. Specified "private browsing mode" in Preferences/Privacy & Security/History. Rebooted system. Haven't visited the blacklisted site for 2 days. Even added another site, one I have never visited before at all, to the blacklist. On the the Pi-hole server flushed memory with restartdns. In my opinion, all possible caches should have been flushed.
I dont know how "private browsing mode" deals with browser cache but most browsers allow to clear all cache easy.
You dont mention you cleared DNS cache for you client OS too ?
You can query Pi-hole or any other DNS server directly with below one on a client (no client cache involved):
