Emby prefers IPv4 over IPv6 after initial server connect

[train_wreck 0]

This is a behavior that I have noticed for a long time and on practically every different variation of server/client OS. The scenario is that both the Emby app and the server both have dual-stack IPv4 and IPv6. From a completely fresh app install, I go to add the server, and can either give it the IPv6 address manually or give it a local DNS record that has both v4 and v6 records (A and AAAA). Upon entering the user/password, the client app will successfully connect to the server over IPv6 THAT FIRST TIME. Any media watching, no matter how long, will continue to use v6. However, if I reboot the client device, or change to a different server within the client app and then go back to the previous one, it will always use IPv4, and from that point on will ONLY use IPv4. This is evident in both extensive network packet captures I have made, as well as on the screen with the list of servers; the URL displayed for the server is always a v4 address. I have tried setting up an Emby server that only has IPv6 addresses, and in that case the client will of course continue using v6. 

This is obviously low priority, but just wanted to point this out. The logic for determining which to use should ideally always prefer v6.

[ebr 16169]

5 hours ago, train_wreck said:

should ideally always prefer v6.

Why if it is a local connection?

You posted this in the Android TV forum but it appears this is an issue for you regardless of the app?

The Android TV app is definitely going to prefer v4 because some of the components within it do not fully support v6.