Forwarding all network ports except one range

[bertaboy]

I'm making a dedicated Direct Connect server, and what I want to do is forward every port on one interface except for the ports required by Direct Connect (As it turns out, according to http://kbserver.netgear.com/kb_web_files/n100495.asp it's all ports except 375 - 425, which to me appears to be a large range for one application....) Now, I also have a bandwidth limit, which means that I can only have 5GB of data transferred over 7 days, including upstream as well as downstream. Any of you know of what precautions I can take for when I turn off the computer behind the server/firewall? Would the firewall respond at all to any requests that have nowhere to go beyond it?

Also, I'd like to make sure that the forwarding is only for one ethernet interface, as I'd like to be able to ssh into the server occasionally to check in on the log files and edit the config files. This shouldn't be a problem as long as I'm behind the firewall, correct?