FOSS gamedev and creative worlds

I trying to make a Minetest Server but sometimes or more often my Friends get a Timeout error if they want to come in. I have tried it with the method to start the server from minetest, so write nothing in the Adress line and with port 30000 and with the method to start the server with ./minetestserver but very often my friends get an timeout error. I give them always my ip from to example http://www.whatsmyip.org/ or http://www.whatismyip.com/. We all came also in the public servers from the minetest wiki. One of my friends came sometimes in the server but we dont know why...

I play on Ubuntu 11.04 via WLAN

And another question: why i have in some versions something in the hand in others (in current, self compiled versions too) nothing?

P.S. sry for my bad english ^^

Timeouts are normal.They happen in Minecraft too.
To avoid Timeouts you should connect to Internet via LAN.

Forward the port 30000 (in both TCP/UDP, since I'm not sure). By the way celeron55, does Minetest use TCP or UDP?

UDP