When trying to connect between two macbook's on a local wireless network we get the following.

1) Start up two copies of 14w33c
2) on one of them, start a single player game
3) hit "open to lan"
4) on the second laptop open the multiplayer menu
5) The game appears in the menu.
6) double click to connect
7) A little time passes
8) Get the following message

Failed to connect to the server
io.netty.channel.ConnectTimeoutException: connection timed out:

tl:dr
The computers can see each other, and the server shows up in the connection menu, but all connection attempts time out.