Using NextDNS - why is Ublock Origin still catching lots of ads?

Something I struggle with: I am using NextDNS (via YogaDNS) and Ublock Origin (on Firefox). Both are configured to use the exact same filterlists. My assumption would be that Ublock Origin would be sitting idle, as all the ads are filtered out at the DNS level, thus never reaching my browser in the first place. However, that is not the case, Ublock Origin still catches plenty of ads.


Could someone explain this to me? Much appreciated.

9replies Oldest first
  • Oldest first
  • Newest first
  • Active threads
  • Popular
  • Ublock blocks before DNS happens, that’s expected.

    Like 1
    • Olivier Poitrey Does that logic extend to every adblocker? Like say Adguard Browser extension too?

    • Jermaine Potts it extends to every browser extension based ad blockers.

  • OK, thanks. But I am still confused, sorry.

    My understanding would be:

    1. A website is requested by the user, and alongside with it all the ads on the page.
    2. For the website and its content to be displayed, DNS requests need to be made to different servers.
    3. If it is an ad-server, the request is denied by NextDNS at the DNS-level.
    4. Then the content comes back to the browser (but without the ads, as these are already filtered out).
    5. The adblocker in the browser would sit idle,  as the ads never reach the system in the first place.

    Where is my mistake in thinking?

  • Ben said:
    Where is my mistake in thinking?

    Adblockers block requests (before a DNS lookup), not responses.

    (their rules are primarily using hostnames not IP's)

    Like 1
  • OK,  now I understand, thanks.

    So in essence I could uninstall extensions like Ublock Origin or Privacy Badger, right? The blockage would then not happen on the request-level in the browser, but a millisecond later at the DNS-level.

    Or, in other words, is there any use at all for adblockers & Co in the browser, or is the blocking at the DNS-level 100% comparable (or even better/ preferred from a privacy PoV)?

  • A reason to keep using an adblocker in a browser: cosmetic filtering.

    Also, from a privacy point of view a browser extension might be better: filtering happens at your machine instead of a sever hired/owned by NextDNS.

    Like 1
  • I know I'm replying to this a year late but thought I'd just add this in case it is useful for anyone searching on how to use NextDNS with cosmetic filtering. My solution has been to use uBlock Origin with all its block lists turned off then add custom filters to it zapping all the white ad spaces on the sites I use regularly - so NextDNS is blocking the ads and uBlock Origin is tidying up the page. Obviously not a solution for general browsing but a decent workaround for sites you use all the time.

    Like 1
Like Follow
  • 2 days agoLast active
  • 9Replies
  • 423Views
  • 5 Following