Utility to Map Remote Port to Local Port

I have a lab Windows 2000 box that has on a separate network segment
attached to it a device that needs NTP access. I don't really want to run
a separate NTP server on the lab box, but would prefer to have it open a
hole to the main network's NTP server. Is there some shareware utility
out there that will map a remote UDP and TCP port to a local server port?

If the lab box has three segments attached to it, I want a way to have the
box pass connections by UDP or TCP to port 123 (NTP) on just the segments I
designate to a a remote IP on a port that I designate. I'm not adverse to
buying this product if a good commercial product is available at under $100.

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Will