Ideally they all need to be on the same subnet eg. 192.168.10.xx if that is your local subnet.
It may be able to find other IP's but as you noticed it can take time for the routing or wont work at all.
Log into the Linux side and set the IP's as you need there are a few ways with the YUN including it net interface which is usually easiest.
There is also a quite major update for the YUN's mentioned in the YUN section which is where we will ask the mods to move this for you.