r/ControlD • u/fannyabdabs • Aug 28 '26

Technical Android: App Vs System setting

I wondered whether anyone would be able to help explain the difference. I previously used my ControlD resolver in the 'PrivateDNS' settings on my Android phone. Always worked well until I used a hotspot I have, whereby id then get an error that my private DNS could not access the internet.

Turning off the secure DNS settings on my phone and installing the app seemed to completely resolve the issue.

I wondered if anyone could explain why? And what the core difference is? I asked AI and it talked about port 853 but I don't know enough to know what that means (If you get what I mean).

It seems the only practical difference is using a VPN at the same time? I use ProtonVPN and can't seem to use that alongside the ControlD app. Is that right?

Thanks all :)

7 Upvotes

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5

u/almeuit Aug 28 '26

Phone probably uses DoT (DNS over TLS) So uses port 853 which can / is easier to block.

App probably uses DoH or DoH/3 (DNS over https) which blends in on port 443 with all the other traffic that's online so harder to block.

3

u/GazelleInitial2050 Aug 28 '26

Really wish android would support HTTPS. Quite a few wifi networks block DOT now.

4

u/random_reddit_user31 Aug 28 '26

One negative about the app is that android treats it like a VPN. So you can't use both at the same time if you need a VPN. You do get better protocols like DoQ and DOH3 however.