Many people think just starting lbz and clicking START SERVER is enough...
Too bad: this is not true, setting up a working server takes some work!
When u just start a server nobody will be able to join!
Well: like all games u need to open up the right port in your firewall.
For lbz this port is 10100.
Usualy you have to specify the protocol that is used to. lbz uses the UDP protocol.
Next: you will have to configure your router to send the packets for this port to YOUR COMPUTER.
Most people dont know how to do this.
It usualy means that your modem needs to be configured using a special web-page on your modem.
Try clicking 1 of these links:
Router at 10.0.0.138
Router at 192.168.1.1
Router at 192.168.0.0
Is one of these links displaying a page where u can change stuff on your router?
If not: read the manuals u got with your internet connection for info.
If it does show a page: look for option like NAT or NAPT.
This differs for most routers. but this is where u can configure what packets go to what PC.
I know that this is not easy: but running a correct server is simply something that requeres a bit of knowledge!