I'm asking for my son. He plays a game online called "Blockland" and they have the option to "host a server."

What exactly does that kind of thing mean? Is it bad to do?

He can't seem to do it anyway cause of firewalls. We turned the XP firewall off on his computer, but we are all networked through phonelines and have DSL which I guess has a firewall in the router also.

Sorry for being so vague, I'm not sure on this terminology.

Any quick ideas on how he can host a server (or a game?)