Well,
do the stuff one at a time.
First assign to your server a private IP address, in the range used by your company on your private LAN
Then give it your router's private address as a default gateway ( necessary if you want your server to respond)
Then comes the tricky part:
you have to get a public address for your server that is going to be used for Network address translation. This is this address that's going to be seen from the internet.
As soon as you grabbed this address (generally supplied bu your local ISP), configure NAT on your router or Firewall, depending on where it's actually done for the other servers of your company so that public address is mapped to private address of the server. (remenber that the server only deals with the private one and is unaware of the public one)
So now you have made a translation from the public domain to your company's private domain.
You just have to set the correct policy rules on the router and the firewall to let OFP games in.
For this, configure both the routers and the firewall to let port 22XXX (i don't know the exact number but it's written in OFP when you start a multiplayer game) in and out. Also let icmp in and out if you want to ping it but be careful to security holes in this case.
hope this helps
Dave
