Fire OS in its current version (126.96.36.199 on Generation 12 devices) does not correctly support mDNS (.local) domain resolution in its browser or in third-party applications when using the default resolver library. This bug, which was fixed in Android mainline several years ago, is a very serious problem that makes working with Internet-of-Things devices challenging to impossible.
Multicast DNS, is a system that computers use to discover other devices on your local network. Devices can publish their name and a list of services that the devices offer. Other devices can then discover those services.
The main reason for using multicast DNS is because IP addresses in home networks change. Constantly. When you have a power outage and your Wi-Fi hotspot reboots, suddenly all of your Internet-of-Things devices have a different IP address. So using IP addresses is completely infeasible.
Thus, mDNS support is the only usable way to do such diverse things as:
- Controlling IP video cameras
- Controlling computers on your network with VNC
- Configuring many Internet-of-Things devices
- Accessing network-attached storage servers
- Accessing internal web servers for thermostats
And so on. Support for mDNS is built into all major operating systems, including Android, by default.
Unfortunately, this basic networking functionality does not work on any current-generation Fire devices, presumably because whatever DNS resolver library you’re using in place of Google Play Services is missing that key piece of functionality.
Solving this problem likely requires making sure that avahi-daemon, bonjour/zeroconf, or some other mDNS resolver library is installed on the devices, and may require additional configuration or code changes, depending on what modifications Amazon has made.
STEPS TO REPRODUCE:
- Get on a Wi-Fi network that has at least at least one device that publishes a web service using Bonjour/mDNS.
- Type that device’s DNS name into the Silk browser.
- Observe that it cannot find the host.
- Observe that every single device in your household that wasn’t made by Amazon can find the host without any difficulty.
- Repeat with a few more Fire tablets until you are convinced that the people complaining about this on Reddit know what they’re talking about.
This is known to be broken in Fire OS 8. Other versions may or may not be affected.
This is not caused by DNS-over-HTTP. I have verified that disabling that feature does not fix the problem.
Third-party apps are also affected, i.e. this is not specific to the Silk browser.
There is an ongoing Reddit thread here: