Selfhosted @lemmy.world Shimitar @feddit.it 2 mo. ago

Issue with local DNS and Android

I have a home network with an internal DNS resolver. I have some subdomains (public) that maps to a real world IP address, and maps to the home server private address when inside home.

In short, i use unbound and have added some local-data entries so that when at home, those subdomains points to 192.168.x.y instead.

All works perfectly fine from Windows and from Linux PCs.

Android, instead, doesnt work.

With dynamic DHCP allocation on android, the names cannot be resolved (ping will fail...) from the android devices. With specific global DNS servers (like dns.adguard.com) of course will always resolve to the public IP.

The only solution i found is to disable DHCP for the Wifi on android and set a static IP with the 192.168.x.y as DNS server, in this case it will work.

But why? Aynbody has any hints?

It's like Android has some kind of DNS binding protection enabled by default, but i cannot find any information at all.

13 comments

The phone or browser may be using DNS over HTTP (aka DoH), check if you can disable it for the wifi network. You may have to disable it on the phone or browser to get your desired behaviour - look up directions for your browser.
Do you have private DNS enabled on Android? That would use a public DNS server by default regardless of what DHCP configures.

Also check your browsers, some have their own DNS settings.
- Private DNS is disabled.
  
  And even ping from tmux fails...
  
  Strange, have you checked the interface info on Android to see what DNS info it's getting from the DHCP server?
  
  Also check that it's getting an IP on the 192.168.x.y network, and not some other subnet if the AP is doing funky things.
You mentioned ping. If you're using Termux you may need to manually update its DNS settings (different from the system DNS). The file is /data/data/com.termux/files/usr/etc/resolv.conf

To make it roam you probably want your home dns first then some internet resolvers after that.
- Thanks! This explains a few things... But not why Android is IGNORING my DNS pushed via DHCP even if private DNS is disabled...

Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:

Fewer Letters	More Letters
AP	WiFi Access Point
DHCP	Dynamic Host Configuration Protocol, automates assignment of IPs when connecting to a network
DNS	Domain Name Service/System
HTTP	Hypertext Transfer Protocol, the Web
IP	Internet Protocol

5 acronyms in this thread; the most compressed thread commented on today has 11 acronyms.

[Thread #933 for this sub, first seen 23rd Aug 2024, 06:15] [FAQ] [Full list] [Contact] [Source code]

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