novirium
commented
3 years ago The lack of mDNS support (specifically, being able to resolve .local domains) on Android browsers has been a giant pain for anyone developing or using IoT devices for years now. That said, I think there's some confusion over what's actually needed here, and what the Android native NSD provides (which people keep mentioning whenever this comes up).
Android NSD provides network discovery, and only network discovery (using DNS Service Discovery). It's clearly using mDNS internally, but it doesn't actually provide any interface to resolve a specific .local domain (like a user would enter into an address bar) on demand - instead the only way to use it is to activate the listener and sit there, hoping that the desired .local address shows up. It really isn't intended for this use-case - it's intended to be able to present a user with a list of discovered devices that support a given service, and for the user to then select one.
Instead, what would be really useful would be just plain mDNS support, able to acquire an Android multicast lock and resolve a .local domain query when it is entered into the address bar. I expect this would have to be implemented from scratch though - the only implementations I've seen working on Android (like DotLocalFinder) have been based on low level implementations like the MDNSJava library.
This would not only open up a whole range of IoT user interactions (many local network devices with a web interface register a .local address for it with mDNS), but Firefox would become the only Android browser supporting it - the standard response to users asking why their .local address isn't working would become: "Well, yeah - you need to be using Firefox!"
stale[bot]
peey
certuna
Toby-Haynes
csadilek
Steps to reproduce
On a LAN, fire up a linux machine with avahi-daemon (or equivalent mdns program).
On firefox, try to visit
machine-name.local:portExpected behavior
We're able to connect to
machine-name.local:portActual behavior
"Unable to connect" error message
Device information
Please note that while searching for mDNS support on android in general, I found a few articles from several years ago saying it's not supported by the OS, but I found a claim about support being available in Android API 16 and up via "Network Service Discovery" library.
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