Previously when I asked about "how to have online gaming (specifically

counter-strike) using a netware firewall several months ago" the
following was replied to me:

1)The firewall admin will need to allow stateful UDP to 27010, 7002, 6003, 27011,27012 and 27015 - 27025 on public hosts.

2)In addition, if the NetWare server is doing Dynamic NAT, then each
counter-strike client on your network will appear to have the same IPaddress to the public server.. to get around this, you must use a
"client port" to each client... you simply add a -clientport 27xxx
to the shortcut on each machine. One machine could get 27000, the next

27001, the next 27002, etc. As long as they are unique all should be
to play on the same server.