LAN server detection fails when IPv4 is not present

A device that has no IPv4 connectivity - but IPv6 - will be unable to discover LAN servers.

The client logs the following warning in the “Multiplayer” screen:

[Render thread/WARN]: Unable to start LAN server detection: Network interface not configured for IPv4

The problem can be reproduced by starting the game with

-Djava.net.preferIPv6Addresses=true

while being in a IPv6 capable network.

Cause:

• The client discovers LAN servers only via the hardcoded IPv4 multicast address 224.0.2.60