Am I right in thinking that a device will probably cache the resolved IP address from a DNS query if that query is made before the name is entered into the PiHole blacklist?
I'm asking as I have some odd things going on with ads while watching ITV Hub on a NowTV box. Everything was fine with no commercials for a couple of days, then last night some commercials started to appear, I assumed that perhaps ITV had added an alternate source for commercials so started up a PiHole trace. The strange thing is that if I closed the ITV Hub app, then restarted it, the commercials didn't come back for a while but they did come back after about 30 mins. I currently have 'itv-ads.aimatch.com' blacklisted and wonder if the app or the box has another address in it's DNS cache.
I tried blocking toots-a but ITV Hub stopped working on the NowTV box. It was odd that ads started to appear last night & are gone today so wondered about the DNS cache.
I found these domains by viewing the query log and just using trial and error blocking individual domains until it behaved the way I wanted it to (did the same for All4).