I and a friend play minecraft, and with the recent 1.3.1 release we can now open our games to LAN ^_^
Or we can sometimes, sometimes we can't, sometimes we can, it's quite confusing, and we're not sure why it's happening.
See if I open my minecraft game to LAN for people to connect, it says in chat they can connect on IP:port. Sometimes this IP takes the form 5.xx.etc... which is my hamachi IP at the time. When this happens my friend also on Hamachi can connect as expected.
Sometimes however it says 192.168.0.x and he cannot connect, because minecraft is listening on the wrong network adaptor. This also happens on his machine sometimes. We're not sure why it happens sometimes and not others.
How do we fix or control this? We've had the issue on both OS X and Windows 7.
We initially had it trying to connect a macbook air to a PC running windows 7. Apparently Minecraft had picked up the virtualbox network adaptor and had decided to start listening on that, rather than the local LAN. Disabling that adaptor fixed the issue, but disabling the internet will render the Hamachi adaptor unusable.