From official RR game help file:
"
THIS GAME ONLY ALLOWS PEER-TO-PEER CONNECTIONS. PEOPLE BEHIND DIFFERENT ROUTERS CAN NOT PLAY AGAINST EACH OTHER. PEOPLE BEHIND THE SAME ROUTER (THE SAME OFFICE, SCHOOL ETC) CAN PLAY AGAINST EACH OTHER. IF YOU USE A FIREWALL, ALLOW TRAFFIC OVER PORT 1626.
If you are behind a router, you can not challenge other people behind other routers. You can however challenge people behind the same router or firewall, for example your friends at school or the office plus everyone connected directly to the Internet.
If you use a personal firewall - allow traffic over port 1626 and you will be able to play everyone.
"
I wonder what that personal firewall really is... and wikipedia tells the answer, the question remains can you get one free and is it really that good?
from wikipedia:
"
A personal firewall is an application which controls network traffic to and from a computer, permitting or denying communications based on a security policy. Typically it works as an application layer firewall.
A personal firewall differs from a conventional firewall in terms of scale. A personal firewall will usually protect only the computer on which it is installed. Many personal firewalls are able to control network traffic by prompting the user each time a connection is attempted and adapting security policy accordingly. Personal firewalls may also provide some level of intrusion detection, allowing the software to terminate or block connectivity where it suspects an intrusion is being attempted.
"
