From the little I understand of networking, this might mean that other machines on the network will never get that traffic (unless the Switch routes it and those machines use it as gateway, which is unlikely).
I think we can safely assume something that needs 20k odd ports forwarded to it won't be doing anything like re-routing and acting as a secondary gateway on the network. It doesn't strike me that a lot of thought went into how a Switch would be used behind a firewall during the design if you need that many ports.
