Assuming it's not a kind of DoS attack, and since it sounds like they can detect the abusing clients (maybe by User-Agent)... some very desperate technical options involve serving an alternate small blocklist that does one of: 1. Try having it block subsequent requests for EasyList itself, just in case the frequent update requests are made with the prior blocklist in effect. (I accidentally did this before, in one of…
Now you're thinking with portals