Telecom Italia locks my DNS server (I cannot change it).
I ended up using PIHole as DHCP, to drive home devices to PIHole, and control my privacy.
The trick is simple: disable DHCP on your router, and activate it on PIHole. As a bonus, PIHole on my RasperryPI2 is way faster than the little chip on my provider Router, and can be patched automatically with unattended upgrades.
Note that there are ISPs that actively hijack traffic to UDP port 53 further inside their network and transparently maps that onto their internal DNS servers.
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And if you can't disable DHCP or set the router in bridge mode, you can just add another router (that you control) between your ISP device and the rest of your network. I've been running this setup for over a decade and didn't run into any noteworthy issues. Leave the ISP-infested router outside your network.
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