Ok found the post in the forums that regarding LAN compatibility.
QUOTE
peppy:
When I started making osu!, this was a high priority feature. I lanned a lot with friends. This no longer happens. I don't know if this is worldwide, but gaming has moved to the internet. I know the benefits of having lan support, but it's not a simple move and requires either a local implementation of Bancho, or huge netcode changes.
If this helps at all.
from
http://osu.ppy.sh/forum/viewtopic.php?f=4&...p;sk=t&sd=a(need to be a member to see it.)