ISPs (and their FCC champions) like to claim they are not telecom services that funnel data back and forth which makes them Title II common carriers, subject to strong FCC oversight.
Instead they say they are information services who process and change data. Then they are Title I services that the FCC has little authority over.
One way they do this is by saying they have DNS, that translates domains into IP addresses.
Of course that's incidental but the more that people actually use alternative DNS, the clearer it is that DNS services aren't core to their offers, and the more evidence there is to show to a court that ISPs are Title II services.
So if you want to support the upcoming return of federal net neutrality protections and FCC oversight of ISPs, one thing you can do is choose DNS NOT provided by your ISP.
"open-source"