[kohtatsu]

They could have had their own resolver before, or even hard coded IPs.

Using software that doesn't respect you is the problem.

[seized]

Firewalls can redirect port 53 to another IP. That prevents things from hard coding to a specific IP.

https://forum.opnsense.org/index.php?topic=9245.0

[kohtatsu]

Euh, it prevents a custom resolver sure, but hard-coded IPs bypass the need for DNS completely.