[SSJKarma]

its TCP/IP !
it doesn't work o a lan, unless you're lan is connected on the net !
why ? because the game NEEDS to connect to the server ! and its the only way to connect, so if you're lan isn't connected to the net then the game won't work.

in any case, if you use a router, then you're router is the firewall, so unless you know how to set up your router for it to disable the integrated firewall and/or set it up for you to accept the port, then you are lost... you cannot host a game !

if you don't , then its your computer who has a problem or you have a software firewall !

in ay cases, the cynchronisation problem is due to those and i doubt it to be about the type of connection either !

SYNC = TCP/IP, since UDP is always UNSYNC
hope this answered your question about it !